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No person who was born blind has ever been diagnosed with schizophrenia (vice.com)
687 points by SZJX 6 days ago | hide | past | web | favorite | 246 comments

If you’re wondering about how common this should be:

if schizophrenia occurs at a rate of 0.72% in the population (McGrath et al., 2008) and congenital blindness occurs at an estimated rate of 0.03% in people born in the 1970s and 1980s (based on Robinson et al., 1987), then the joint probability of a person having both conditions, if the two are independent, would be 0.02% or 2 out of every 10,000. Although this is a low prevalence rate, it is higher than the rates for childhood-onset schizophrenia (Remschmidt and Theisen, 2005), and many other well-known medical conditions (e.g., Hodgkin's lymphoma, Prader Willi syndrome, Rett's Syndome). Based on this estimated prevalence rate, in the United States alone (with a population of 311, 591, 917, as of July 2011, according the US census), there should be approximately 620 congenitally blind people with schizophrenia. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3615184/

That does do rule out misdiagnosis etc, but it does seem to support a correlation.

Just so we are clear: the approach taken in the studies described is “we looked at a bunch of blind people and couldn’t find a schizophrenic”, and “we looked at a bunch of schizophrenics and couldn’t find a blind person.”

The appropriate question is: can such an approach, in a wildly fractured series of data sets, overlook 600 people?

It sure can, but the odds are against it overlooking all of them.

Of course, maybe the genes leading to blindness and schizophrenia together also lead to some other defect that results in miscarriage or some other kind of early death.

To be clear: the odds are against it assuming no confounding interference. And given that, I don't know that an error of 600 is really that much of a statement. I mean, just to invent an example (not the only possible one, obviously!):

Congenital blindness is likely diagnosed with near 100% certainty in early childhood. It's easy to spot. The same is very much NOT true of mental health problems. Schisophrenics are diagnosed, almost always, when their condition manifests in such a way to interfere with their life (or someone else's) to the extent that the doctors get called in. There are widely assumed to be LOTS of undiagnosed mental health cases in society, simply because the sufferers live in situations where their disorder can be managed (or suppressed!) in an ad hoc way.

Now, the question becomes: are blind people more likely to be living in a circumstance where their mental health troubles are more easily managed/ignored/suppressed without the involvement of doctors who would otherwise diagnose schizophrenia? That seems not at all unlikely to me.

And frankly: this kind of confounded measurement strikes me as MUCH MORE likely than a heretofore unrecognized link between vision and schizophrenia. Significant results require significant proof, and I don't think this is it.

> are blind people more likely to be living in a circumstance where their mental health troubles are more easily managed/ignored/suppressed without the involvement of doctors who would otherwise diagnose schizophrenia? That seems not at all unlikely to me.

Could you explain your thinking to me? I'd think that people with one serious condition would me much more likely to have a second serious condition diagnosed, purely because of increased attention from medical professionals. That's certainly been my experience.

The issue is that psychosis/schizophrenia isn't like testing for a bacterium or looking at an x-ray. It's really a label for a set of presenting behavioral patterns, and is heterogeneous (I don't mean this critically, just the way it is).

So let's say someone is blind, and they come in. They will almost certainly be more likely to receive attention than someone who is not. But how their presenting disorganized thoughts, etc. are described is likely to be different given their history of blindness, especially if they had a lifetime history of associated cognitive deficits or issues.

It's also the case that overlapping presence of two pathologies is not necessarily same as them disjointly. So blindness etiological factors + psychosis etiological factors may not equal schizophrenia with blindness, but rather a more severe cognitive and/or physical disorder that receives an entirely different diagnosis. This latter scenario isn't necessarily a measurement issue, but it could be construed that way.

>But how their presenting disorganized thoughts, etc. are described is likely to be different given their history of blindness, especially if they had a lifetime history of associated cognitive deficits or issues.

Another thing to consider is that a lot of people with mental illness can tell something is wrong with them because they can compare themselves to others. It's much harder for a blind person to do that because they don't get a lot of the information most people get passively by simply being near other humans.

I have (untreated) asthma, but nobody ever explained to me what having asthma means. I was well into my adulthood before I found out that it is not normal to have difficulty breathing hours and sometimes days after simple aerobic activities. And I didn't even have the issue that I couldn't see that other people didn't have this issue. I just thought that this was normal and they were better trained.

> I'd think that people with one serious condition would me much more likely to have a second serious condition diagnosed, purely because of increased attention from medical professionals.

Does that apply to blindness at birth, though? I mean, you don't get continuing "treatment" or checkups for blindness, right? (At least, no more than a sighted person would go in for a yearly eye exam.) Obviously there are unique needs a blind person has to function in society, but it's not like something like cancer or a mental illness where you need to follow up and have continuing care and treatment for many years, possibly the rest of your life. For birth blindness, it's basically "yep, kid's blind; need to adapt to that", and that's it from the standpoint of medical care, no?


That depends on the specialty, if the symptoms are overlapping and the treatment produces strange side effects - that diagnosis could be delayed for many years.

There are other links between vision and schizophrenia - e.g. https://www.wired.com/2009/04/schizoillusion/ (although that may better be described as a link between visual processing and schizophrenia. vision -> visual processing is a fairly well accepted link however, so vision -> visual processing -> schizophrenia seems plausible enough to look at a bit more.)

Significant results do not require significant proof. This is a common misunderstanding. All hypothesis would require the same amount of proof, regardless of a person’s biases going into it.

You're just being pedantic. That's not helpful. Obviously the point here was about "credulity", not proof. The very existence of a replication crisis in statistical science like this is an existence proof of what I meant. You don't just take papers like this at face value. You can't. They're simply wrong too often.

In the kind of first principles sense you are thinking of, sure, proof is proof. But in the real world the burden of proof for an epidemiological headline like this absolutely is much higher, in the practical sense of "should I believe this bullshit or is there a mistake somewhere?"

This is a good point but similar kinds of phenomena could lead to something more benign but equally problematic.

For example, let's say someone inherits (genetically or environmentally) etiologic factors for psychosis and blindness. It's possible that whatever these factors are, they are severe enough to have widespread enough effects that the person no longer receives a psychosis diagnosis, but instead some other diagnostic label that's more comprehensive in nature.

Schizophrenia is really just a label for a semi-heterogeneous set of pathologies that might be labeled something else. I'm not saying that these problems don't exist, just that how they are perceived and described might vary a bit from scenario to scenario (this is one of the main impetuses for DSM-III and later actually). So someone with one pathology might receive a diagnosis of schizophrenia, someone else, bipolar disorder, and yet someone else developmental disorder NEC/NOS.

It's entirely possible that if there is a negative correlation, it's because one reflects some preventative factors for the other, or something like that, but it's also possible that whatever causes the conjoint presence of the etiologies is catastrophic, leading to death, like you suggest, or the need for some entirely different label.

This could be a simple survivor bias. These are two highly debilitating conditions, chances are that they simply don't live long enough if it's severe, or if they do it just remains without diagnosis.

You'd think there'd be case histories for it, though, if it was just that schizophrenia led to an early death for blind people.

Only if it was diagnosable as schizophrenia

>Of course, maybe the genes leading to blindness and schizophrenia together also lead to some other defect

There are many potential causes of being born blind, not all of them genetic.

Given that this is something that is talked about as a phenomenon, a psychiatrist encountering a congenitally blind, schizophrenic person would be really inclined to publish a case report... (e.g. not a 1 in 600 chance, and people with chronic mental health conditions tend to encounter more than one psychiatrist).

Maybe that's the plan all along. 'huh strange correlation, let's put this in a paper, wait for case reports'. Might not be a bad process, if explicit.

An analog version of Cunningham's law!

I didn't open my stats book to confirm this, but my hunch is that you can estimate the likelihood of what we observe (0/300M) with what we expect (600/300M) in the following way. Think of 1 six sided die. The odds of not rolling a six is 5/6. In two rolls, the chance of not seeing a six is 25/36, in 3 rolls (5/6)^3. At 4 rolls, the odds of not ever rolling a 6 are 0.47, at 20 rolls 0.02 and at 30 rolls 0.004.

So in this case, the category is being both born blind and developing schizophrenia. The odds of a single person being in this category are 2/1M, and the odds of a person not being in the category are 999998/1M. The expression for never observing a person in the category for a population of 300M is ((10^6-2)/(10^6))^(300x10^6). Wolfram Alpha says this is equal to 2.6x10^-261.

It is very unlikely that the two distributions for blindness and schizophrenia are independent!

The number 600 would be the number of expected blind schizophrenics in the US right now. But as people have been looking for them over time, the actual number should be higher.

Just a moment, 0.72% x 0.03% = 0.0002%, which is about 2 out every 1,000,000.

To be fair, it appears they fixed the math later, or at least roughly. (2 out of every 1M) x (the US population) [they cite ~311M]. That gives 622. Not far off the 620 they report in your quote.

This is like having a weighted coin that comes up heads with probability 2⋅10⁻⁶, flipping it 311 million times, and seeing 0 heads. That's astronomically unlikely.

To see this, observe that the number of heads follows a binomial distribution with n = 311 million and p = 2⋅10⁻⁶. This can be well approximated¹ by a normal distribution with mean μ = np = 622 and standard deviation σ = Sqrt[np(1 - p)] = 25.

99.7% of the time², when you sample from this distribution, the sampled value will be within 3 standard deviations of the mean, i.e., between μ - 3σ = 547 and μ + 3σ = 697. Results further from the mean are more unlikely. For example, seeing a value more than 7 standard deviations from the mean (i.e., less than 447 or more than 797) is about a 1 in 2 trillion event³. Since 0 is about 25 standard deviations from the mean, the probability of seeing 0 heads is on the order of 10⁻¹³⁸.

[1] https://math.stackexchange.com/questions/2021801/conditions-...

[2] https://en.wikipedia.org/wiki/68–95–99.7_rule

[3] https://www.johndcook.com/blog/table-of-normal-tail-probabil...

> This is like having a weighted coin

Tangent: there is no such thing. You can weight a die, you cannot weight a coin.

Intuitively this should make sense because even if you made one side of the coin from lead and the other from balsa wood, all you are doing is changing the center of gravity of the coin. The coin spins about its center of gravity, not the geometric center of the coin, so this makes no difference.


Possibly, though if we want to be pedantic "weighting" has shifted from merely meaning "increased in weight" to meaning "biased through manipulation" - colloquially you can describe a situation as "weighted against someone" if you think that person may be unfairly disadvantaged - like in a multi-talent contest a continued draw of activities that favor one party using a hidden method that is suspected to be directed to the end of favoring that party.

You absolutely can manufacture unfair coins either using a two surfaced approach (like a weak magnetic field acting on a magnetized coin) but even a one surfaced approach is possible if you make use of carvings on the surface of the coin to get a favorable result from air resistence - lastly you can even achieve it through density, if one side of a coin is significantly more dense then the other then it will tend to land face down - you can play with this a bit by trying to flip a weighted cylinder and observing the landing pattern - I might suggest taking a coin roll (like you get in a bank) and gluing some coins into one end of it - then try and flip it in the air so it lands coin-side up.

It is, however, very hard to bias a coin significantly without skewing the dimensions or having clear alterations visible on the coin.

To add to your point: I ran some experiments a while back with curved coins. The coins have to be absurdly shaped before the shape affects the outcomes:


Falling below the noise floor is different from proving no correlation. Negative results for a given experiment simply mean it’s below an the experiments ability to detect.

Aka, you need to pick a threshold for bias that’s interesting before designing the experiment. A casino might care a great deal about say 0.5% bias which would take a lot of trials to detect.

I respect the level of free time taken to run and publish this experiment!

Interesting results, I thought they'd be more skewed.

The parent comment that a coin of lead and balsa wouldn't be biased, but to clarify, the linked research paper states it can't be biased unless allowed to bounce/spin. Maybe your weighted cylinder flipping is not biased if you throw+grab instead of letting it land?

> Possibly, though if we want to be pedantic "weighting" has shifted from merely meaning "increased in weight" to meaning "biased through manipulation"

Not sure what your point is here. Yes, that is the meaning that is being discussed. You understood it yourself. Grandparent understood it as well. What value do you feel bringing up this point brings to the debate?

> like a weak magnetic field acting on a magnetized coin

Probably not. The field will act through the other face of the coin as well. The coin is pulled towards the magnetic surface, but it doesn't alter the revolution of the coin. If the field is sufficiently weak to not pass through the coin then it wouldn't have any impact on the other side either.

The exception would possibly be mu metal or something else that prevents the magentic field from acting on one face entirely, in combination with a strong magnetic field, and I'm still going to lean towards "probably wouldn't work". It would still intermittently pull the entire coin towards the surface, it's not clear that it would counter the rotation of the coin itself.

> even a one surfaced approach is possible if you make use of carvings on the surface of the coin to get a favorable result from air resistence

No, because air resistance is acting on both sides of the coin at once. The air resistance is a constant A+B, not A,B,A,B.

> lastly you can even achieve it through density

No, this is the entire point of the article. The coin doesn't revolve around its geometric center, it revolves around its center of gravity. By changing the density of one side (balsa wood and lead, as I said) you change the center of gravity but the coin itself has the same rate of revolution.

> Grandparent understood it as well.

Considering you were the grandparent, I guess that should be somewhat reassuring.

FWIW, I interpreted your use as rigid in the same manner as the GP (of this post).

As far as I’m concerned a electronic bistable generator that is biased through manipulation is effectively a “weighted coin”.. those exist.. and are counter to your claim unless you restrict “weighted coin” to the completely literal.

> Considering you were the grandparent

God no, GP here means the contextual grandparent of the topic, as it always does. GP means the person I responded to. Why in the world would I respond to myself just because "GP"?

If you haven't read the rules, you need to be giving the most gracious reading of the comment chain here. Pretty obvious what the implication was. Try reading again.

> As far as I’m concerned a electronic bistable generator that is biased through manipulation is effectively a “weighted coin”

Oh cool you're trying to impose a change of topic from the ability to literally bias a coin when a normal person flips it randomly, into telling me to defeat... all attempts of people manipulating all RNGs ever?

Super weird angle for a discussion about flipping coins. Not really interesting.

That paper is not good support for your pedantic argument. (More pedantically, any coin without uniform density is "weighted" by definition, regardless of toss bias)

In fact, most methods of coin toss will be influenced by an unbalanced coin in some way. The paper only demonstrates that if you flip a coin with a certain precisely specified method (and catch it midair) - can you be reasonably assured a weighted coin will be unbiased.

See their own referenced book Jaynes, 1996 pp 1003-1007, which I think gives a much clearer explanation of the possibilities.

Note that the NFL for instance does not catch the coin, so there's at least a real world where a coin could be biased.

The important part of that paper is this:

"Examples of how others have flipped and tossed coins show the students how essential it is to carefully describe the experimental process." not just the one detail about angular momentum and CoG.

That paper redefined what it meant to toss a coin making their concussion meaningless in practice. For a more in dept real world analysis.


PS: Of note they where detecting bias in the range of 1% that’s difficult to detect by hand.

You're presenting it like your article substantially rebuts the point. When the absolute best bias you can do is 1% above random that's pretty much "fair" as far as practical usage.

It's not even clear that's a real bias or just random noise, or an anomaly of their testing setup.

>Tangent: there is no such thing. You can weight a die, you cannot weight a coin.

Yes but you don't need such a coin. You can use a perfect coin and consider flipping it many times.

Example : https://www.youtube.com/watch?v=Vo9Esp1yaC8

It could be made to make a difference in air. Imagine a styrofoam coin with one side padded with an extra layer of lead.

(For best results, make the styrofoam thick relatively to the lead, and/or attach extra aerodynamic surfaces :).)

There are examples in that paper of scenarios of effectively influenced coin tosses...

I feel like it's not super difficult if you're catching the coin, if you're able to position the coin in the same place and apply the same force consistently you'll largely get the same height and speed of rotation. When I was a bored kid I was able to get a pretty consistent coin toss where it would land on the opposite of the side at the beginning. [0]

[0] Of course I didn't do any statistical analysis or a huge number of trials for this to really tell if I was able to do it but it felt pretty consistent.

A magnetic coin, might be the "trick coin" that was being posited.

I wonder if you could build a (admittedly thick) coin with some sensing/actuation going on in order to make it land on an arbitrary side.

The same is true for a die :-) It could make a difference for the coin if you “rolled” it instead of catching it in the air.

That's only true if you test all 311 mio for both. While I think that blindness is self-analyzing, that's not true for schizophrenia.

So how many blind people were evaluated for schizophrenia?

This might actually be a lower percentage than for normal-seeing persons. People are less experienced with the behavior of blind people, so it's harder for surrounding people (and probable even for the blind themselves) to recognize it and push people to go get diagnosed.

> Since 0 is about 25 standard deviations from the mean, the probability of seeing 0 heads is on the order of 10⁻¹³⁸.

Note: the above figure comes from the normal approximation to the binomial, which loses accuracy towards the tails. The exact probability of seeing 0 heads is (1 - p)^n = (1 - 2⋅10⁻⁶)^(311⋅10⁶) ≈ 10⁻²⁷⁰ [1].

[1] https://www.wolframalpha.com/input/?i=%281+-+2+*+10%5E-6%29%...

Another way to get there is that, given N shots at a 1/N event, you expect 0 hits 36% of the time (1/e).

You can divide the population up into into 600 groups with 500000 people in them, and each of those has a 36% chance of not ever hitting.

So seeing no cases is like flipping a 36% coin 600 times and hitting 600 times.

Your 'approximation' is doing a lot of the work here.. Since you have a binomial distribution why not just use it directly?

(1 - 2e-6)^(3e6) ≈ 0.002

So about 0.2%. Still highly unlikely but orders of magnitude more likely than what your normal distribution-detour gave.

> (1 - 2e-6)^(3e6) ≈ 0.002

Using the binomial directly is a good way to get the probability of 0 heads. Note, though, that the U.S. population is in the neighborhood of 300 million, not 3 million (as you seem to have used).

(1 - 2⋅10⁻⁶)^(3⋅10⁸) ≈ 10⁻²⁶¹


Except we don’t have perfect information. Schizophrenia is misdiagnosed fairly frequently. I couldn’t find stats on undiagnosed schizophrenia, or schizophrenia diagnosed without visual hallucinations (which is probably the more relevant metric)

Wowsers! That's quite the elementary math mistake in a journal article. I'm tempted to track down the authors and point this out to them.

Or the journal editor, you definitely should. This is the kind of thing that can easily get cited in future work on the matter.

I sent an email to editorial.office@frontiersin.org. If they reply, I will post their response here.

Subject: elementary math error in journal article

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3615184/ was linked to and discussed today from Hacker News (a popular discussion board for software engineers) here https://news.ycombinator.com/item?id=22307445.

In the ensuing discussion a poster noticed that the journal article contains an elementary math error:

"if schizophrenia occurs at a rate of 0.72% in the population (McGrath et al., 2008) and congenital blindness occurs at an estimated rate of 0.03% in people born in the 1970s and 1980s (based on Robinson et al., 1987), then the joint probability of a person having both conditions, if the two are independent, would be 0.02% or 2 out of every 10,000."

0.72% * 0.03% is actually .0002% or 2 out of every 1,000,000.

Despite the article being several years old, I thought you might want to know.


Great job; we need more good citizens like you!

I was unaware that they do at least have the implied 620 figure for the entire US correct, so there is hope that this is just a localised typo.

I can't get over how stunningly-similar this is to the infamous Verizonmath!

Well it's been a day and, sadly, I've received no response. The error also still appears on the publication's own website:


Thank you for your effort. For someone who is in academia and a firm believer in the advancement of knowledge via peer-review, these things matter. Cheers!

it is probably not a math mistake since, when they applied the probability the 620 people is correct. Might be a typesetting (formatting) mistake. The 0.0002 is already a percent, but someone overlooked that and turned it again into percent.

Still it should definitely be corrected as the 2 out of 10,000 is a value that sticks in the mind.

I once helped setting an article in tex (originally written in word) and made the mistake of not noticing that rich text 10^20 got converted to 1020 in plain text. We only noticed post print but nobody else seem to have stumbled on it even though it was at the core of the articles thesis.

They also used the 2 in 10,000 figure when picking out the comparison syndromes. I believe Retts is ~1 in 10,000. It's definitely not 1 in a million.

My guess is the editor somehow messed up the per thousand sign ‱


edit: My bad. Correct character, incorrect description. It is indeed "ten thousand".

Somewhat ironically, I think you're off by one character here.

Unicode U+2031 ‱ is actually the per ten thousand sign (check its character name).

Unicode U+2030 ‰ is the per thousand (or "per mille") sign.

The one thing worse than off-by-one errors are off-by-zero errors.

Weirdly, as ChrisRR points out, they get the total number of predicted blind + scizophrenic people in the US correct. So it almost looks like more of a typo than a math error.

But still.

It makes sense, because as a scientist you often only write it as e.g. 0.2% for the article, but 0.002 in your actual calculation.

Percentage calculations being off by 2 zeros I would say is one of the most common mistakes I saw in, e.g. statistics exams.

So even then, 600 people in the US should be both born blind and scizophrenic

That isn't a guarantee that 600 people will be born with both.

Obviously there's no guarantee, and there's also the fact that we may not have every case documented, but if it is true that we have 0 case documented, that's pretty far from 600. Even if it's not "impossible", then at the very least it's less likely.

It's a simple binomial probability calculation. The probability of one or more blind schizophrenic people born in the US, assuming they're independent variables, is 1-0,999998^330000000. I don't have a calculator on hand that can calculate that, but it's more than 1 - 10^-87. So the odds that there is no link between the two is close to the odds of guessing a specific bitcoin wallet's key in one try.

No, the .02 is correct. If you ignore the percentages part (since both left and right side use it), you're doing

  0.72 x 0.03, which is indeed 0.02
If you do it as probabilities not expressed as percentages, it's 0.0072 x 0.0003, which is 0.0002, but that's 0.02%

You can't just ignore the percentage signs.

0.72% expressed as a decimal is 0.0072. 0.03% expressed as a decimal is 0.0003. 0.0072 x 0.0003 = 0.000002. Expressed back as a percentage, that's 0.0002%.

> it's 0.0072 x 0.0003, which is 0.0002, but that's 0.02%

No. 0.0072 x 0.0003 = 0.00000216‬ ~= 0.000002 = 0.0002%

You're right. Not sure how I fell into that trap so easily.

I wonder if it's better to treat percentage as a unit or variable. So a-percent x b-percent = c(percent-squared), or c divided by 100 twice.

You could also replace % with 10⁻² and use scientific notation:

      0.72% ⋅ 0.03%
    = 0.72 ⋅ 10⁻² ⋅ 0.03 ⋅ 10⁻²
    = 7.2 ⋅ 10⁻³ ⋅ 3 ⋅ 10⁻⁴
    = 7.2 ⋅ 3 ⋅ 10⁻³ ⋅ 10⁻⁴
    = 21.6 ⋅ 10⁻⁷
    = 2.16 ⋅ 10⁻⁶
    ≈ 2 in 1 million

It's because we usually dont multiply percentages, but instead work with normal decimal figures.

Could there be a much simpler explanation?

The most recent study the article sites (Morgan et. al, 2018) states that out of 468k people in the population "1870 children developed schizophrenia (0.4%) while 9120 developed a psychotic illness (1.9%). None of the 66 children with cortical blindness developed schizophrenia or psychotic illness."

If we don't assume there is a relationship between schizophrenia and cortical blindness, it's not surprising that none of the 66 people who had cortical blindness developed schizophrenia. Simple binomial approximation will yield a 77% (0.996^66) probability. Am I missing something?

Also I find the difference in prevalence rates of schizophrenia of 0.4% in the Morgan et al. paper vs 0.72% in McGrath et al. 2008 odd.

Morgan et al. 2018: https://www.sciencedirect.com/science/article/abs/pii/S09209...!

Found a link to the full paper here: https://www.gwern.net/docs/psychology/2018-morgan.pdf

It explains the difference in prevalence rates: "While median lifetime morbid risk for schizophrenia is estimated to be 0.72% (Saha et al., 2005), many of our young cohort had still not passed through the window for schizophrenia onset."

However, their claim for a relationship is indeed very weak: "In our data, this dropped to 0.2% for congenital or early peripheral blindness and was zero for congenital or early cortical blindness [0 cases out of 66]. Our data further suggest that the protection offered by cortical blindness may extend to a broader range of psychotic disorders and that risk of psychosis may effectively be reduced to zero."

It's ironic that they start the discussion stating "The results from this whole-population cohort, although possibly underpowered, lend confidence to findings from smaller case studies". Yes, it is underpowered, and I'm surprised it was published.

I mean, if it is genuinely a whole population cohort, there's a legitimate question to what "power" even means in that context, because there's no statistical uncertainty. It simply is.

Whether or not hypothesis testing in registry data is justifiable was once the topic of a legendary fight in my graduate department during someone's defense.

No that’s not correct.

I mean if we’re evaluating the claim that no blind people got schizophrenia then sure. But the claim is that blind people don’t get schizophrenia, which is different. The population for this claim is not “all the humans alive” but rather “all potential humans” (which is not possible to sample).

I wonder if there's no genetic correlation, but rather a brain input correlation. There is more brain input from vision than any other input possible. Since the brain is mostly a device that builds connections based on prior input, a condition like schiz may not develop simply because of the type and amount of data going in may not be enough to trigger the autistic, multiple personalities, and other depression related conditions.

> There is more brain input from vision than any other input possible

Is this really true? I would've imagined it to be hearing, though tbh I'm unsure how one would begin to approach measuring them in isolation.

You have, at birth, around 3,500 auditory hair cells per ear (https://en.m.wikipedia.org/wiki/Hair_cell), so 7000 inputs to process for sound. Sure your brain does a lot with that information to project a 3D sound field from two ears, but that's the limit of the input.

The adult human eye has around 70 million cones and 75-150 million rods (https://en.m.wikipedia.org/wiki/Retina). There's a bit of crazy data compression that goes in to this, but the amount of information to process from the eyes is several orders of magnitude greater than from the years.

> You have, at birth, around 3,500 auditory hair cells per ear (https://en.m.wikipedia.org/wiki/Hair_cell), so 7000 inputs to process for sound. Sure your brain does a lot with that information to project a 3D sound field from two ears, but that's the limit of the input.

> The adult human eye has around 70 million cones and 75-150 million rods (https://en.m.wikipedia.org/wiki/Retina). There's a bit of crazy data compression that goes in to this, but the amount of information to process from the eyes is several orders of magnitude greater than from the years.

While you're technically correct, that's not the whole story.

There is a substantial amount of image processing that happens in the eye (I suppose it's possible that's true of the ear as well; we know much less about hearing than sight). I'm not familiar with all the research in the area, so I can't throw out numbers, but you can't just compare numbers of raw sensors meaningfully.

I agree, there's so much about the brain we don't understand, plus whole sections overlap or process multiple sources. Nothing is simple in the brain! In terms of the amount of your grain required or dedicated to each input this says nothing.

However, the statement was:

> There is more brain input from vision than any other input possible

I guess we could compare the nerves that lead from the sense organs. Again from wikipedia:

> Each human optic nerve contains between 770,000 and 1.7 million nerve fibers

> In humans, there are on average 30,000 nerve fibers within the cochlear nerve

so again, at least an order of magnitude more nerve connections from the sense organs to the brain. I think this backs up the original statement.

Interestingly the number of nerve connections from the cochlear are greater than the number of raw sensory inputs, but the eye is quite the opposite. I know the input to the brain is more of a differential coding between colours than raw data from the cells.

> you can't just compare numbers of raw sensors meaningfully.

Why not? It's certainly not definitive, but assuming a correlation between number of sensors and dataflow is certainly a reasonable starting point. If you really want to suggest the number of raw sensors is meaningless with regard to data volume, that seems like a much bolder claim. Especially when, as here, it's a 4-5 order of magnitude difference.

nice technique to focus on the raw transducers/sensory cells counts! That's fundamentally the raw inputs we're dealing with.

you can look at the mass dedicated to each sense I suppose and use that as a proxy, occipital lobe vs temporal lobe. Couldn't land a search hit on those quickly though.

Just from a signal processing perspective, sound is a 1D data type, though we do have stereo sound and can localize sounds, so that's some additional processing there I suppose. There's also frequencies involved. Image processing is typically more demanding than audio from what I understand with computational things, images being 2D, or 3D sources. This is a pretty interesting exploration relative sensory input load.

I wonder if there's a philosophical correlation.

Mental breaks from reality are increasingly common as society increasingly condones and encourages escaping reality in many ways, including recreational drug use, television and video game addictions, and even physical mutilation.

Yet this isn't happening with those who were born with one less way to perceive reality. Perhaps it's because those born blind have a greater and stronger need to hold fast to reality, themselves not being able to benefit from it nearly as much as everyone around them and as much as nature would have it.

It's a compelling narrative - especially for social conservatives - but ironically it's without much basis in reality.

Schizophrenia rates have declined significantly over the past century, and have been stable over the past 20 years. If anything, the data better supports the opposite story - that as societies develop more sophisticated ways of altering conscious experience, people are less likely to be schizophrenic.

But more soberly, I'd say there's probably no link at all, and that both narratives just reflect a misunderstanding of the pathology of schizophrenia.

https://www.mentalhealth.com/mag1/scz/sb-time.html https://www.researchgate.net/figure/Time-trends-in-GP-record...

Then we should be looking at the occipital lobe, no?

Did you mean "does not rule out misdiagnosis"?

Going further than misdiagnosis, how many congenitally blind people are even tested for schizophrenia? Maybe lack of visual hallucinations make it less likely someone would get to the point of a test at all?

> Maybe lack of visual hallucinations make it less likely someone would get to the point of a test at all?

(I am not a psychologist!)

Visual hallucinations are not a hard criterion for diagnosing schizophrenia. They do occur, but the symptoms are more about delusions, disorganised thinking and catatonic symptoms. IIRC hallucinations are more often auditory, like hearing voices.

I know, that's not my point, I'm saying the barrier may be that a blind schizophrenic person may not even be aware that there's anything seriously wrong or worth bringing to a doctor's attention, so he would never get to the point of a psych evaluation.

They would still exhibit bizarre behavior, delusions, paranoia, catatonia etc. Patients heavily rely on family & friends to help manage their illness. It's very much something all-encompassing.

Then by definition they wouldn't be mentally ill, as mental disorders have to cause significant distress for the patients to be diagnosed as such.

By this logic we are speculating that perhaps being blind from birth blocks the symptoms of schizophrenia to the point that it is no longer a "disease". I don't know if this is correct, but a compelling idea.

Yeah that would be the speculation: that blind schizophrenics are asymptomatic.

I think you are assuming that significant distress will result in awareness that the distress is medically significant.

I have no assumptions about schizophrenia, I just paraphrased how the definitions of the ICD-10 work. The fact of suffering is the distinction between a mental disorder and a quirky personality.

Think of it as a continuous spectrum from the idealized normal person (the center of a bell curve) to the person having significant problems living a normal, fulfilling life. The eccentric personality is somewhere in between.

This is all about definitions. The ICD-10 and similar categorizations essentially work by listing a number of symptons and a minimum count of symptoms a patient has to have to be diagnosed according to this definition. They don't make any assumptions about disorders existing per se.

It can be distress which is missed by the doctor.

I think it's far more acceptable for us to "mishear" something and think nothing of it. The seeing also have the backup sense, sight to verify much of what we hear.

"I heard the sound of an elephant stomping around in my living room."

This statement made by a seeing person could be made by nobody thinking much of it. I wouldn't immediately ask if they actually thought an elephant were in the living room at the time.

The same statement made by a (blind) schizophrenic person could have implied that the person actually believed there was an elephant in the living room, but the clinician might have missed the significance and not asked follow up questions.

A bit of a contrived example, but you get the gist.

To a seeing person it might

This theory depends on hundreds, maybe thousands of doctors and peditricians, many of whom would be specialists focusing on blind patients, a similar number of teachers, social workers, care takers, blind training centers staff, parents ... ALL missed schizophrenia, which is often a debilitating illness, because they are "sighted".

That’s confusing. Schizophrenia is horribly unpleasant for the person who has it, they aren’t “tested” so much as they are suffering terribly and seek help and are then given a diagnosis.

It’s not like screening people for spectrum or personality disorders.

I the schizophrenic people I know are afraid of authority and avoid anything that might diagnose them. It takes a forceful family member to get them to a doctor (or in one case the prison system), and constant attention to get them to take the treatments. In general if they are not a harm to society or themselves it is best to let them live alone in a small town (small town because it gives the town gossips something useful to talk about: the talk helps ensure everybody knows to watch out for the victim, and small ensures even new people in town know about the situation)

Note, my sample size is far too small to draw universal conclusions about schizophrenic.

> the schizophrenic people I know are afraid of authority and avoid anything that might diagnose them.

Since blind people need to rely on others a lot more than people with sight, I think it would be even harder for them to avoid medical authorities than for other schizophrenics. For what it's worth, the schizophrenics I knew personally were not averse to seeking help for their condition, but were very distressed by side effects from medication (understandably!)

> Schizophrenia is horribly unpleasant for the person who has it

There's a strong cultural component to how schizophrenia manifests. Violent, paranoid thoughts are more common in societies like the United States. The extent to which their experiences can fit into a positive cultural narrative partly dictates their quality of life. The U.S. is exceedingly hostile in that regard. You're likely better off in a society where hearing voices is considered a gift from the gods, or where perceiving odd but intriguing cause+effect relationships suggests you can sense magic.

Metasource: https://www.theatlantic.com/health/archive/2014/07/when-hear... ("But a new study suggests that the way schizophrenia sufferers experience those voices depends on their cultural context.")

Googling will show similar reporting in the literature over several decades. I don't think I've seen any contradictory research, though that's not surprising as this is just an interesting observation; there aren't any sophisticated, concrete explanatory models to critique--individualist vs collectivist dichotomy seems intuitive but not concrete on its own. Rather the focus seems to be on pragmatic therapy. It's noteworthy nonetheless, particularly as a reflection of American society, and of how culture informs pathology, a point usually made regarding more touchy-feely mental health issues and thus lacking punch.

Visual hallucinations are not at all the main symptoms of schizophrenia. Besides, blind people do "see things" under the influence of psychedelics.

Your math is wrong. The probabilities you listed for the 2 events is correct, but you multiplied 0.72 by 0.03,but probabilities aren't stated that way. 0.72% is a probability of 0.0072 and 0.03% is 0.0003. So the correct probability of coincidence is much lower than 0.02% it's 0.0002% or a probability of 0.000002. So that rate wouldn't be 2 in 10,000 it should be 2 in 1,000,000. This pravelance rate is therefore 25 times lower than that of childhood onset schizophrenia (1 in 40,000).

You did however get the number of people who should have it in the US correct at roughly 620 cases if the two conditions are independent. Although that only includes the reported population numbers, as a better population estimate to account for people who won't answer the census is more like 340 million. This portion of the population that doesn't answer the census could easily be hiding all 670 potential cases because they also don't tend to trust doctors and would never be diagnosed.

I'm not saying that this is a guaranteed scenario, but schizophrenia does have a genetic component, so it is possible that we simply haven't seen the cases in the general population because their families have hidden the affected family members. The "closet" syndrome when it comes to mentally ill family members is well documented, and some groups have even been known to hide family members with physical disabilities such as blindness or deafness. We believe this is happening less today, but that's difficult to prove and may simply be our way of coping with the fact that we will never be able to help people trapped in that situation.

That’s another possibility alongside misdiagnosis, normal privacy, etc. I personally doubt any single factor is going to hide discovery of blind from birth vs blind as a young child globally. But with populations this small a few is all it would take.

PS: That’s a direct quote from page 2 of the link. It’s got some other interesting information about this topic you’re interested.

I seem to be missing what to anyone who's ever had to deal with youth services is the obvious alternative:

Schizophrenia, like almost all diagnosed psychological disorders, is called a diagnosis, but is effectively a punishment. Psychiatrists feel sorry for blind patients and refuse to apply this punishment to them, for the same reason they wouldn't punish them for performing a little worse at basketball.

I don't know. In most of the civilised world, diagnosis unlocks options that were previously not available.

In what part of the world would you rather be sick and undiagnosed than have your illness acknowledged?

Any place with red flag laws, including the USA. A diagnosis can make you a second-class citizen with fewer rights.

I doubt many blind people are applying for firearm licenses.

Unsurprisingly, disabled people still want to exercise their constitutional rights[1]. Blindness isn't a binary condition, there are millions of legally blind Americans with enough usable vision to own and use firearms responsibly.

[1] https://www.usatoday.com/story/news/nation/2013/09/08/iowa-g...

What do you mean it's a punishment?

Schizophrenia diagnoses are generally applied to individuals with a mix of behavioral problems and "abnormal or undesirable" thought patterns. It's a broad brush that isn't applied based on hard biological data like an MRI of the brain, but on observed and reported behavior at the discretion of the psychiatrist and rough adherence to DSM guidelines.

Typical treatments like Haldol, Thorazine, and Depakote have a blunting and depressive effect on the entire central nervous system. Treatments like shock therapy, cause severe memory loss and permanent brain damage.

These "treatments" are often paired with coercion, involuntary injections, confinement in psych wards, and court orders.

Many times LE will bring a civilian to a psych ward as a secondary or additional option to charging them with a crime. It's often seen as an additional tool in creating orderly communities, disciplining individuals that get out of line, and overall exerting control on society and free thought and action. Once a patient is admitted or diagnosed, they are strongly incentivized to align themselves and their behaviors to the values and expectations of the institutions and people that brought them there and control their release and treatment plans.

Even if schizophrenia had a biological signature it wouldn't be used in practice because they WANT the ambiguity and discretion to classify and medicate patients as they see fit.

Do you have a diagnosis or have anyone in you family with this debilitating disease? Where do you find the nerve to post such misinformation as this? From personal experience, my family member who suffers from this condition has been hospitalized several times in psychosis and every time he comes out he is glad and happy that it's over and he is back to his normal self. The pharmacological therapy has horrible side effects but spreading FUD like this is way over the line. You also only list the older generation of medication, there are many new ones with less side-effects. Learn a bit a about the alternatives, the neurotoxic degenerative effects of the disease and the prognosis without treatment. With every new psychotic event there is less chance of getting the person back. And, yes they do MRIs and there are visible changes in the structure.

I was diagnosed schizophrenic -- among other things -- in an in-patient program for children.

The parent is sensationalizing a good bit, but I agree with his overal point: treatment of schizphrenics -- and other "untouchables" syndromes -- is very poor.

Antipsychotics are hell. Full stop. Even for next-generation pharmaceuticals. Risperidone took away the delusions, and every other faucet of myself that made me human. Can it improve quality of life? Yes, it can. If the case is severe enough that the patient is endangering themselves or others (through violence or neglect), antipsychotics can sedate their impulses and delusions.

I would describe it as a short-term (if ceased within a reasonable timeframe) chemical lobotomy. No hyperbole.

I was lucky that I'm fairly educated, quick of mind, and primarily presented with negative symptoms (catatonic subset). Delusions and psychosis are transient, and I'm able to reflect on them, identify when they pop up, and not act on them.

For someone that is in a near-constant state of psychosis, antipsychotics are really al that can be done, but I personally would rather be dead, than a husk. If I were still on them, I probably wouldn't believe this because the drugs would take away some of my agency.

I'm now on a hefty dosage of a certain dopamine agonist, and it has improved my quality of life immensely. There are stil bugs, and psychosis and delusion are much more common now, but I have a good grasp on them and wouldn't want to to back to being a shel of a human.

It's dehumanizing and violates my dignity.

I would disagree that the parent was just sensationalizing, they implied malice and thought-control by the "evil" doctors. There's no hidden agenda, no conspiracy. We don't know the illness well enough and the treatments are nasty. But the doctors are doing what they can to help people, and like you said, it does help. And the psychiatrists always try to lower the dosage to a minimum to avoid the terrible side-effects. From what I've seen haldol and leponex are nothing short of miracle drugs, they worked when all else failed. The disease is dehumanizing, not the treatment.

I'm sure it depends wildly on region and class status, but parent comment is largely correct in parts of USA.

Haldol, Thorazine, and Depakote are older but still widely used, even for disorders like bipolar. Even atypical antipsychotics are still life-changing, personality altering, potentially diabetes-inducing heavy handed tools. You yourself admit the side effects are horrible. It's far from FUD. Be glad your family member is getting appropriate treatment.

How is the parent both right and I should be glad my family member is getting treatment? This doesn't make sense. If the treatment is worse and used to control undesirable thought patterns (that's what the parent claims) than surely you mean to say the alternative is better? Ie, letting the illness take its course and the delusional thinking set in. Or what are you saying? Because it doesn't make much sense to me.

> It's often seen as an additional tool in creating orderly communities, disciplining individuals that get out of line, and overall exerting control on society and free thought and action.

This morning in my country an allegedly deranged 41-year old man stabbed a 16-year old girl to death. The media reports that he underwent psychiatric treatment in 2018. I will take the liberty of translating roughly one of his facebook posts to show you some "abnormal or undesirable" thought patterns, as you call them, and why appropriate treatment is necessary.

> Today when they tell me that they have checked the first floor check above us, the apartment is the last name P., first name I.D., if the commanders report that they did not pass the check, the team that went into the apartment and they pretend to do some kind of check or what do I know supervision, let alone protecting us officials, they have an announcement after the order has been issued exactly as long as they have to scram out of the apartment as our commanders give them. We are the dead guard, then there is no such thing as a stop, I stopped, who goes, the password, the response, the Praetorians. The dead guard shoots, slaughters and then only checks when it is resolved that the protected natural persons are safe near the action and only then reports to the proper authorities.


1) you can get locked up, indefinitely, based purely on the diagnosis. And while "it needs to be in your interest", it is in the interest of the people making that decision to do it (they're paid for that decision).

2) you can't drive. There's ways around it, but they involve extra courses and costs.

3) There's many things you can't do. From getting a security clearance to working in the police force, certain legal professions, certain medical professions ...

4) as a kid, let's not go into just HOW bad psychological treatment is.

5) medications against this are basically drugs. They're strong sedatives that don't help, except by sedating you in the moment.

6) those medications have side effects. Like all sedatives they can kill you, cause sleep problems, depression, hallucinations, "freezing" (weakness, up to total inability to move), tremors/shakes, eating problems. AND a common and interesting one: you don't consider the long-term consequences of your actions under the influence of these drugs, up to total unscrupulousness. Which brings us back to problem no. 1.

7) worse, if you go over the recommended dosage and duration the side effects generally become permanent. Eventually what happens is what people call "zombification". Summer Glau (or whoever ...) could come to your bedroom and offer absolute "anything goes" and you would not be able to lift a finger. Those recommended doses and duration are essentially nothing (enough for a mild high at best), and somewhere between hours and weeks depending on the exact drug.

8) EVERY psychiatrist and EVERY institution does not just go over those limits, they exceed them by years, factor of 10, "for lack of alternative". (meaning the alternative is having people watch those patients, much more expensive)

8) I guarantee the patient will be the one blamed for it, not the drugs, not the science itself (that clinical psychology has no answers for problems other than sedation), and not the nurses/docters that exceed the recommended dose by a factor 100.

> population of 311, 591, 917,

Is this a thing? People write numbers like that?

I found the absurd over-precision more problematic. There probably were exactly that many people in the USA at some instant in time in this century. For a minute or two at most. 310 million is a more sensible way to report the population.

If the authors of the study can’t multiply percentages, I don’t see why I should believe the study at all. Taking their numbers at face value: .72% * 0.03% = 0.0072 * 0.0003 = ~0.000002 = 0.0002%. That’s 2 per million, not 2 per 10k. Nice try.

edit: somehow they did get the expected number in the US right, but they seem to have flubbed the comparison to other conditions.

Being blind since birth likely reduces the probability of being diagnosed with schizophrenia if you have it - because you will know that everything you "see" is hallucinations so you won't act on them.

That changes the math significantly.

That would be true if visual hallucinations were the primary symptom of schizophrenia but that is not the case. https://en.wikipedia.org/wiki/Schizophrenia#Positive_symptom...

With odds like that, they would have to sample a much larger population directly for the results to be statistically significant.

wait... is this math error in the actual article? or just in the vice text?

I think the vast majority of schizophrenics have relatively mild symptoms (just as most diseases have more sufferers of a mild version vs. more severe version) and their diagnosis is made primarily because they have a disease that makes it hard for them to be 100% self sufficient, and there needs to be a paper trail in place that documents this.

Although the majority of blind people have essentially 100% self sufficiency (maybe with some occasional help from family/friends on some edge cases) I suspect it is relatively easy for a congenitally blind person to get financial and other assistance in the US, since as a society we are fairly supportive of people with obvious congenital disabilities. I could therefore imagine that if there was mild schizophrenia in a congenitally blind person, there'd be far less incentive for the affected person or their family to establish a formal diagnosis to this effect.

I wonder if this could be a partial explanation for this surprising statistic (and the lack of evidence for severe schizophrenia could maybe just be due to inadequate sample sizes in the OP study to detect this smaller set of people.)

Very interesting. I wonder if there's a link between melatonin production in the pineal gland (affected by visual perceptions of light) and endogenous DMT, also suspected of being produced in the pineal (see Rick Strassman's work)

For a long time endogenous DMT, or some other endogenous psychoactive compound, was suspected of being a cause of schizophrenia. I think it's largely discredited by now anyway.

The endogenous psychoactive idea is fascinating. My friend called me during a psychosis, and I was convinced he was having a really bad psilocybin trip.

Modern research has actually found closer ties between psychosis and a different psychoactive compound: dynorphin[1]. In terms of recreational drugs, this is the neurotransmitter responsible for a salvia trip.

From an outside standpoint, this makes more sense than the classical psychedelics. Unlike LSD or psilocybin, salvia hallucinations usually result in a total disconnect from reality, and the user is often rendered catatonic like in severe cases of schizophrenia.

[1] https://www.sciencedirect.com/science/article/pii/S000632231...

I remember some of the first time I did salvia. I was sitting on a couch at the end of a room, and I looked up at the corner of the ceiling, where the ceiling met two walls. Then I looked back at the people I was sitting with, but all I could see was the corner of the ceiling, where the ceiling met two walls. Then after... seconds? A minute? An hour? I could see normally again, but the room I was in began to move backward. It detached from an enormous wall, where it was revealed to be one of an infinite grid of identical rooms.

I don't remember the rest. Apparently all I did the whole time was stare with a blank expression for five minutes.

Salvia. It's powerful stuff!

A neverending salvia trip... I would not wish it upon my worst enemy.

>Unlike LSD or psilocybin salvia hallucinations salvia . . . user is often rendered catatonic.

Woah! Granted I’ve see only seen a handful of people use it, but it’s the only drug which I seriously worry about it causing agitation/frenzy so severe as to induce outward violence.

Doesn't psilocybin work by overloading serotonin receptors in the brain? Seems like you could achieve that without DMT.

It's interesting that in the study they described, performed on blindfolded people, that their descriptions have similarities to the DMT experience:

>>> One subject, a 29-year-old woman, saw a green face with big eyes when she was standing in front of where she knew there was a mirror—though she couldn’t see it. Another 24-year-old man, by the end of the second day, was having difficulty walking because of all the hallucinations that appeared to be in his way. He reported seeing "mounds of pebbles, or small stones...and between them was running a small stream of water." By the end of the study, he reported seeing "ornate buildings of white-green marble" and "cartoon-like figures."

EDIT - Too late to edit my original post, I should correct myself and say the theory has not been discredited (according to Dr Strassman himself)

Melatonin is broken up by sunlight exposure through the eyes, perhaps endogenous DMT might be impacted in a similar way?

the discordianists were right

> *THE PINEAL GLAND is where each and every one of us can talk to Eris. If you have trouble activating your Pineal, then try the appendix which does almost as well. Reference: DOGMA I, METAPHYSICS #3, "The Indoctrine of the Pineal Gland"

DMT, you say?

It's entirely possible. My friend Jamie has a video about that.

Maybe the visual center has more trust over auditory or other parts of the brain? For example an auditory hallucination is easily discounted, but if most people witnessed a visual hallucination, they'd question their own sanity because that signal is so trustworthy? There's many other explanations just a random thought.

It's an interesting thought. I wonder if the nature of schizophrenia isn't particularly conducive (almost binarily so) to being "driven" by visual signals.

In my interactions with schizophrenic people (especially when untreated), I've witnessed intense and unusual attention (some would say obsession) devoted to "patterns" — I've no other word to describe it generally; to paraphrase it: "order or regularity in visual, typically geometric or symbolic sequences of objects", a particular fascination for certain shapes or symbols.

Somehow, at some point in the processing, said patterns acquire additional meaning, what I'd call uncanny connections. (Schizophrenic people deeply believe that they see how to "connect the dots" — hence a particular tendency for tinfoil hatism and other paranoid world views.)

It also seems to work with music and other sensory inputs, though, but as you said, it could be that the visual is beyond some threshold, or of a particular nature so as to be able to trigger the schizophrenic patterns.

There's also this history of violence with the onset of schizophrenia, it seems to be an acquired condition notably highly correlated with childhood suffering (of abnormal magnitude and length), but with possibly typical genetic or epigenetic predispositions. This tells us again to search for a trigger, and it's interesting that people born blind never seem to experience such a triggering, the onset of schizophrenia, ever.

But people born blind are also different in many other ways, biologically — notably circadian rythms, etc. I should know because although I'm perfectly able to see I experience a few but too many of the same kind of second- and third-order conditions that blind people have, and that led me to suspect it was related to a deficiency of mine in regions of the brain related to the processing of light in relation to time (cycles of melatonin, hunger, etc; iirc it's generally involving the thalamus).

I don't really know what conclusion to make of all this, but I feel these are clues, help narrow or focus the solution space.

I am able to relate to your comment about patterns. I have had two episodes of anxiety attacks. I had visual hallucinations that kept repeating and wouldn’t stop. It was absolutely horrible. When the anxiety attacks used to happen I would stare at the wall for long durations. The wall had bricks in brown and white. I did not like that there was no symmetry. I kept repeating over and over that the wall lacked symmetry. I also experienced myself and my thinking self as two different entities and it as if I could watch myself as another person.

Edit: added the last sentence.

I think I can relate to your experience, from similar anxiety moments under some cocktail of sustances (alcohol and weed for me in my youth).

> I also experienced myself and my thinking self as two different entities and it as if I could watch myself as another person.

Can you expand on this? How was it different from the "third-person" kinda view that we do casually?

Until I experienced, I did know that such a thing existed. After the panic attack I searched about and found an entire Wikipedia article describing it.


To your question, I think third person view is like an intellectual activity that one undertake voluntarily. However what I experienced was very real feelings of separation and not an intellectual role play.

Ok, gotcha, not an intellectual role play.

I think we all dissociate, like it's a spectrum; the weakest most minute manifestation is when we just 'take a step outside of our current state' you know, when you stretch just a bit to be/think/do slightly different. Experiment. Mimicry. We temporarily sever/disable a few 'links' inside and let new connections form, just to see.

It's also how I picture resisting empathy, all these times when we shut down feelings almost automatically — some of it is mundane 'keep a straight face', some of it is deeply atrocious like awful news or misery right in front of you. We have these "mirror neurons" that automatically replicate emotions of those we see¹; and unless we shut it down or temper it, we are bound to feel that very thing too. I think we kinda "dissociate" mildly from these mirrored feelings whenever we must, it's automatic by now (social species must do that to evolve beyond primal emotions it would seem).

But sometimes dissociation gets out of hand, cranked up to 11, and it operates versus parts of your own self, it shuts down entire regions of our inner world, and what's left to see is a weird, paradoxical state, that which psychology and the DSM see and would rightfully call pathological etc.


[1]: That got me thinking, maybe it's one thing people born blind can't do: "see" the emotions of others and trigger mirror neurons in that way. Maybe there's something in this, in the unsufferable realization that you may see but never really know what's inside others, that drives schizophrenic people so obsessed whereas blind people, obviously, can never experience such a feeling. It certainly converts to other senses (voice conveys so much emotion for instance), but hypothetically very differently. I don't know. Thinking out loud here.

Isn't it that when you combine two extremely low prevalence phenomenons together, you can't really make any accurate predictions because the numbers are so low that the error margin is too high? I might be wrong, but I seem to remember something to that effect. Could it be what's at play here?

The thing is, if you had a discrepancy of some order of magnitude (e.g. 6,000 or 60 instead of 600), you could talk about accuracy problems. You could look into rounding errors and margins of errors, like we do with constants in physics, and that would maybe yield some new or modified equations (models).

But the "binary" absence of even 1 single case hints at something else: it's a category thing, there's "in it" or "out of it", and it seems that being born blind somehow means you can't develop schizophrenia.

The absence of any cases is strong evidence against the null hypothesis that the both are independent (assuming the combination isn't just much harder to diagnose), but it isn't strong evidence for it being impossible. Just because something hasn't happened doesn't allow you to distinguish between it being impossible and it being very unlikely (of course the other way around does work, then this is strong evidence that it is possible).

I will yield to your logic, and thanks for taking the time to explain how my approximation was flawed. I really need to brush up my logic skills... I did say "hint" though, which really means it is hypothesis, not strict logic at that point.

Edit: wait, no, I re-read my post and clearly, I did not make the logical fallacy. You're correct, and I did see that, hence using the word "hints at", not "means that". But my wording was bad afterwards ("is" instead of "would be"). : ) so thanks for clarifying.

Or it shows underdiagnois or hard to find almost-never events

Eh indeed, and it could even be that schizophrenia (whatever its "base principle" is in the brain) exists in some people born blind, but presents itself in such a different way that it's misdiagnosed for something else (so categorically, that we already have another name for it).

But I think it's really worth investigating. Could yield important knowledge and may lead to new forms of treatment perhaps.

That paper suffers from a small number problem.

With simple probability, using their 0.4%, it means that you would expect 0.26 blind child out of 66 to have schizophrenia. So that they see 0 is perfectly reasonable. For the other psychotic illness, that probability is 1.5%. So, out of 66 you would have expected 0.99. Maybe that kid is the lot and will develop apparent symptoms of psychosis in the next few years...

In general, an epidemiology study without statistic means that they try to find something but they didn't and couldn't explain why.

Now, common epidemiology statistic are going to use a 5% alpha error and a 95% confidence. So, if they were to repeat that experiment a 100 times, 95 times you would observe a value close to the mean. The probability numbers given are maximum, and I would guess that the minimum is zero. So 95% of the time, you would have a value much lower, and closer to zero individuals out 66 for psychosis.

Even if there's some sort of genetic or environmental barrier, you would think that it would happen at least once as a misdiagnosis.

From my admittedly completely uninformed position, this looks so much like academics searching for some profound insight that will win a Nobel prize (or perhaps just guarantee a tasty stream of research grants) when in reality the truth could be much simpler. Let's look at an example of a group that suffers disproportionately:

'The high level of schizophrenia in black Caribbeans living in the UK probably reflects the interaction of multiple risk factors, many of which cluster in the black Caribbean community in the UK. Particularly significant factors appear to be the combination of isolation and exclusion, both within society (living in areas of low ethnic density and reduced participation in society) and within the family (family break-up and paternal separation). These factors seem to be more powerful than socioeconomic disadvantage, which is more likely to be a consequence than causal. Racism itself may contribute to social exclusion, increasing the vulnerability to schizophrenia. Biological or genetic susceptibility do not appear to explain high rates of schizophrenia in black Caribbeans. More research is needed about the role of cannabis, particularly in its more potent forms, and whether this contributes to the excess of schizophrenia in black Caribbeans.'

Perhaps it's as simple as: people that are born blind are to some extent insulated from risk factors that are conducive of schizophrenia.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2418996/ (just the first article I could pull up on a phenomenon I was aware of)

With regards to being skeptical of scientists and their motivations, I m as myopic as they come, but even to me this is a stretch. This is a legitimately interesting observation, something that does make sense given how big a role our visual cortex plays in the brain. You're right that there are risk factors but they just increase and decrease frequencies. If a factor eliminated this condition, there's definitely need to investigate that further to understand why.

That would be a reasonable explanation I think if the rates of schizophrenia were merely lower amongst the blind. But what's said here is something quite ab it stronger than that: there are zero known cases of schizophrenia among the congenitally blind. If true, and if not simply a sampling artifact, it implies something pretty profound about the nature of schizophrenia as a disorder that has hitherto not been known.

>Perhaps it's as simple as: people that are born blind are to some extent insulated from risk factors that are conducive of schizophrenia.

Isn't that as interesting, too? I admit, I thought it was the takeaway of the article.

I wonder if this points to the problems in the concept of this diagnosis.

It has been seriously questioned since World War II as to whether schizophrenia is even a disease.

The questioners being mostly from the psychoanalytic school (some psychiatrists), all forgotten, may have something to do with it.

In my family more than half of one side of my immediate parent-generation family members have been diagnosed with the disease. Most of them get by with little to no drugs.

All of them were diagnosed in connection with divorce proceedings.

(We had a misunderstanding. You must be hearing voices.)

I could not help but believe, admittedly biased, that this is "health" as a locus of power, blame, and control.

In higher education I had close blind friends who achieved high marks and went on to work in Fortune 500 companies, at a level not unlike people I knew before they got hit with a diagnosis. Did they have disagreements with loved ones? Sure. If they had found themselves in a bitter marriage and divorce, would something they said be weaponized into a diagnosis of mental illness? Maybe. At the rate of the general population? Maybe. I don't know.

I am not criticizing, accosting, or accusing anybody of anything. Just asking some questions.

So what does that imply? That visual sensory input might trigger schizophrenia? But that would imply that blind people have diminished sensory input. I just don't buy that.

They have a lot of sensory input, perhaps as much as seeing people. It's just delivered differently. Try an isolation tank. I can totally imagine someone going crazy in one of those.

The original title was even more click-bait. I'm glad it was changed before posted here.

Light inhibits melatonin release. https://en.wikipedia.org/wiki/File:Circadian_rhythm.svg

Low melatonin levels are correlated with many diseases, including cancer and schizophrenia.

> The results indicated that blind women had a 35% reduced risk of developing breast cancer. Moreover, women who became totally blind prior to age 65 had a 50% reduced risk https://news.cancerconnect.com/breast-cancer/blind-women-hav...

Role of Melatonin in Schizophrenia https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3676771/

Disappointing that the article doesn't mention melatonin once.

Do blind people get less light?

Less light in the retina, yes. But there are different types of "blind."

So at least some blind people would be unaffected by melatonin differences which means you should still be able to find blind schizophrenia cases if the melanonin hypothesis is true

No, they specifically only mentioned people that were "born blind." I was answering your question:

> Do blind people get less light?

Yes, in their retina. But if you want to be technical, blind people 'get' as much light as anyone else on the rest of their body.

Some people born blind will still get the same amount of melatonin as sighted people. Therefore you should still see born blind schitzos. But we do not. The melatonin hypothesis is bunk.

Hallucinations are much more commonly auditory in Scz, and often language based (deaf Schizophrenic people report hallucinating disembodied hands doing sign language). If it is a real effect it could possibly have the opposite explanation- blind people tend to have compensatory improvements in other senses like hearing, so perhaps developmental auditory hyposensitivity is a causal factor.

But yeah, while I think the observation is interesting, it is hard to conclude much of anything from it.

Interesting: https://gizmodo.com/can-deaf-people-hear-voices-1675963437

Apparently, deaf people do get Scz, and some even hear voices.

What if we could “reboot” a schizophrenic brain through some sort of sensory deprivation?

I recently started going to a spa that has float tanks. It's the most relaxing thing in the world, and I highly recommend it.

While floating, the body is able to relax completely, and this has a profound effect on the mind. It really does feel like a reboot.

I did one and was completely angry the entire afternoon after.

I think I relaxed so much my body had to rebound to my normal state of frustration and anxiety.

Laying in a salt bath can also dehydrate you, a lot.

I've felt particularly grumpy after a float session a couple of times and was able to remedy this by rehydrating.

This can definitely happen after things that are supposed to be relaxing. The key is to plan your day out so you don't do anything stressful right after. (unfortunately you probably still have to drive home afterwards)

this is hilarious. sorry for laughing

Do you usually pay by the hour for these services? I'd like to try it but am pretty cost-conscious lately.

Only half-joking here: inflatable kiddie pool, bag of softener salt, and a tarp? Total < $100, brine should keep much from growing so I wouldn't think it would need too much maintenance.

There's also the issue of keeping it at body temp.

Usually you do. I was able to try one of them once via a Groupon or some such local coupon.

It's about $30 per hour in my area. I'd go every day if it were cheaper :)

Reminds me of an episode of House.

For some reason I have doubts that placing a schizophrenic person into sensory deprivation is going to have them emerge better off. Taking someone that is already out of touch with reality and further disconnecting them seems like it would push them further into schizophrenia.

One way I've heard schizophrenia described is that it feels like sensory deprivation; if you sit in an anechoic chamber for hours, you might start to "hear" the things schizophrenics experience in minutes instead. Sensory deprivation has been used as torture, so this does not sound like something you would subject people to unless they were 100% willing and motivated.

Does aphantasia have any impact?

I have aphantasia and schizophrenia. I've never had a visual or auditory hallucination, but I have had plenty of delusions and cognitive dysfunction. Ever since learning about aphantasia I've wondered if it has protected me from these types of hallucinations. Maybe someone should run a study on this?

A common post among the people over at /r/schizophrenia is that the so called negative symptoms of schizophrenia (anhedonia, apathy, reduced social drive, cognitive impairment, etc) are just as bad if not worse than the positive symptoms (hallucinations and delusions). Unfortunately the negative symptoms are not adequately treated by any medicine and are in fact made worse (!) by medication. This is probably the number one reason why schizophrenics quit their medication - the medications are simply so shitty that people would rather risk the positive symptoms than experience worse negative symptoms.

There's no good research directions for new schizophrenia medications either. Schizophrenia research certainly isn't discussed (or have funds raised for it) as much as Alzheimer's research despite the fact that 3.5 million people in the US have it, and it affects people at a much younger age.

Edit: Before starting medication I noticed some visual disturbances related to schizophrenia often known as sensory gating deficits. I would get an overload of visual sensory information to the point where I would notice nearly every detail in my visual range simultaneously (that's the best way I can explain it). At times it was actually quite beautiful since the whole world would pop out in vivid color. However as soon as motion was introduced it quickly became overwhelming.

I have aphantasia and auditory hallucinations.

That would mean that you sometimes hear things in your head, but you have no control over what you hear?

That's an interesting thought. I (think I) have aphantasia and I could easily see how you'd be less inclined to hallucinations, intrusive thoughts and the like.

If you think you have aphantasia, you almost certainly do. I was in the same boat, but after conversations with a few friends I found that the ones which don't give very literal descriptions of their imaginations.

It isn't in any way an analogy, they literally do see the things they're imagining. It's like a hallucination, except with control and full awareness that it's not real.

It's easy to see how that could turn into actual hallucinations, I'll agree.

I do not have aphantasia. The way I think of my imagination is like a virtual machine running a separate reality I'm in control of. I can roll a ball around on a plane in space and still have awareness of "base" reality.

Other -non visual- sensations I am able to simulate: - Taste/smell, able to taste specific foods without eating them - Sound, able to hear conversations, music, etc. - Pain, able to feel the sensation of touching a hot stove or breaking my arm

If any people with aphantasia are in this thread, are you able to "simulate" any of these experiences? Also: are you religious in any way? There is an interesting history of religion and schizophrenia [0].

[0] https://en.wikipedia.org/wiki/Religion_and_schizophrenia

> If any people with aphantasia are in this thread, are you able to "simulate" any of these experiences?

No. Memories are like non-verbal propositional knowledge. You know what happened, you can articulate connected facts about it. But the idea of “hallucinating” a visual memory is absolutely foreign to me. You bunch of crazy people actually see things that aren’t there, in your mind’s eye?

> Also: are you religious in any way?

Strong no, but I fail to see the relevance. I’m atheist for entirely unrelated reasons.

> You bunch of crazy people actually see things that aren’t there, in your mind’s eye?

It's not so much that I "see" them -- it's very distinct from the visual perception. For me, actual sight is associated with some physical feelings - not only do I see objects/colors/etc but there's some degree of feedback from the muscles of my eye, best demonstrated by looking at bright lights vs dim surfaces. It's very, very clear when I'm actually seeing something.

Then, separately from ocular perception, there's an ethereal space inside my head where I can conjure up various "platonic ideals" of things, and the senses they generate. It's like a sandbox of sorts, or perhaps that loading scene in the matrix where Neo and Trinity grab a bunch of guns.

By platonic ideal, i mean that when I think "Apple", I sort of see an apple in that internal space, but it's neither red, nor green - unless I focus on "red apples" in which case it will no longer be green, but also won't yet be specifically a Fuji apple or a Red Delicious apple. It's just an uninstantiated class of "apple.red" existing in my headspace.

No matter how hard I visualize the apple, no matter how many specifics I give it (Fuji apple, small soft brown spot on one side, with broad color splotches rather than narrow bands)...it never activates the "feeling" of real sight. It very much feels like it doesn't exist, a temporary cloud of vapor that just "poofs" away instantly if it's not constantly regenerated.

For me, there's very little way I could see getting confused between my visual imaginations and my visual sight.

Generally when I conjure something up I don't just see it visually, potentially I also sort of taste or smell or can recognize the feel of its texture, and maybe hear associated sounds like the breaking open sound of the apple. Again, all of these are extremely non-tangible and generally would never be confused with real sensations. They occupy a different space.

It's like a simulation and modeling environment with a physics engine, more than anything else. It's a place to run experiments - with or without hypotheses.

Also, almost all my thoughts have a verbal monologue. There aren't "characters" in my head talking to me, it's usually my own voice, but sometimes I can use other people's voices to sound things out as well. Rather different from my internal monologue I can also pull up "recordings" of what other people said to me (which are really generative models, akin to a decoder in machine learning).

That was the best explanation I've heard about this, before reading this I was questioning if I had aphantasia

It's worth keeping in mind that, in the Extreme Imagination Conference 2019 keynote, Prof. Zeman described "about half" of over 2000 folks his team has studied as multimodal. So for roughly 50%, it's purely a matter of visual processing and doesn't apply to other senses (like your examples), while the other half include multiple (or all) senses.

That being said, I'm one of the folks who have to choose how to add spices when I cook based upon what I remember working together in the past. As I understand it, some (perhaps only a talented few and perhaps including some unimodal aphants) are able to use the same part of their brain that processes taste and smell to imagine the taste and smell of new combinations of flavors.

Another quirk: I don't think I get songs stuck in my head in the same way as others. I may have a particular verse or rhythm on my mind... but I'm pretty sure that I'm lucking out in this regard.

In all the cases mentioned, I'm reasonably capable of predicting or extrapolating outcomes based upon past experiences (I don't stick my hand on many hot stoves, for example). But my brain just doesn't seem to run through the process of recreating sensations to get there.

That's interesting. I think I have aphantasia (the way people describe their visualizations seems very strange/foreign to me although sometimes I think I can visualize some things) but I can hear music very well in my head. The other sensations I cannot imagine at all.

Particularly, the idea of imagining pain and feeling it is strange to me.

Well, I'm one so...

No, I'm not able to simulate any of that, in the way I think you mean. I can predict the outcomes, but I can't at all claim to be experiencing any of it. It involves no more sensation than reading words on a page.

(Which is to say, none. I understand that that can also vary. The only time that changes is when I'm dreaming. So I know what experience I'm not getting, I suppose.)

No, I'm not religious, but nobody in my family is. We used to be subjects of the Thunderer; that was a couple of generations back. Christianity managed to break us of that, but not to make us believe them.

This applies to me as well.

I’m not able to do any of these.

I had aphantasia until I had a drug (weed and shrooms) induced psychosis. During the psychosis I had constant musical hallucinations. Now, after recovering, I can now both visualize and have a clear inner monologue in my mind.

This is fascinating. I also have aphantasia and experienced psychosis with high dosages of those drugs, however the only lasting effect I received was a profound connection with all living things. I subsequently became vegetarian. Other lasting effects I have experienced from strong psychedelics are mostly social realizations—basically I have more/expanded empathy and imagination and am able to go far enough outside my own headspace to recognize how I differ from others. I envy people who claim that psychedelics have made them closer to cognitive normal; while they have made me happier in the sense that I have less internal conflict, they have never “fixed” my brain, only given me better coping mechanisms.

I wish that was a repeatable experience.

> If you think you have aphantasia, you almost certainly do.

I took the VVIQ online and it concluded that I "probably don't" have aphantasia (but merely "You do not have a vivid imagination"). Basically it seems that unless you're 0's across the board, you can form some part of some image in your mind, and thus don't meet their definition.

Then again, the only one I rated above a 1 was "gait", and that's as much auditory as visual, so I'm not sure I believe them.

I took another online test which asked me to look at a 3D shape made of blocks, and then later compare others (drawn from different angles) and determine which was the same, without referencing the original. It was an easy test, but to me it had little to do with visual imagery. I just remembered the original shape as sounds (far easier than remembering a shape!), and then picked which of the others sounded the same.

That's the fundamental problem I see with tests that try to figure out how a person thinks. You try to invent a test which you believe can only possibly be solved in one way -- but people who don't think that way already have a lifetime of experience living and thinking, so surely they've developed other mechanisms by now.

It's like saying "I know how to test if someone has two legs: we'll put the finish line 100 meters over there! Then anyone missing a leg won't be able to get to it." Just because you don't have two legs doesn't mean you can't get around just fine.

I'm absolutely sure there are people who solved the block problem visually, and tactilely, and other ways I can't even guess at. I think "aphantasia" is all wrong. It implies visual thinking is normal, and "non-visual" is the only alternative. We don't have a special word for "people who don't have blue eyes". We say directly what color we mean.

Schizophrenia is a grouping of symptoms that are generalized to an inability for a person to smoothly track reality. For example, when a person without schizophrenia attempts to track the trajectory of an object, the eyeballs follow a smooth path. When a person with schizophrenia attempts the same, the eyeballs do not follow a smooth path, with the focal point moving chaotically off center from the target. A part of the diagnostic criteria for schizophrenia is testing whether or not the eye can smoothly track the movement of an object. This would likely be why it is difficult to diagnose someone that was born blind.


Just speculating, but being born blind has (in recent history at least) led to a quite sheltered and protected life. For those cases caused by 'chemical imbalances' (genetic factors), 'sheltering' would not help. For cases that occur in response to the external world (environmental factors), the 'sheltering' might have a shielding effect.

If so, then the not-blind vulnerable should avoid stress.

Interesting. Can it also have something to do with an extremely small sample size? These are both rare conditions so intersection might be even rarer.

Commenter above addresses this. Considering the prevalence of each condition, if they were independent then we would expect that 2 out of 10,000 people should have both together. The fact that zero cases have been found suggests that there is either a diagnosis issue, or that the two conditions are not independent.

That was an arithmetic error. It’s 2 out of 1,000,000.

The total 620 is actually correct again: 0.0072 times 0.0003 times 311591917 is 673.04. I suppose the 53 person discrepancy is due to rounding towards 0.03% but using a more accurate number for the actual computation (e.g. 0.0277%).

You can’t just throw extra digits around like that. It’s a bit unusual and jarring to see the population of the US quoted as “311591917” even if that is the census figure, because such a high-precision number would only be true for about a minute and you don’t know which minute.

Chill please. I used the exact number from the paper as quoted somewhere else in this discussion. Which seems adequate when saying that the authors final number (sixhundredsomething) is most likely correct even if the intermediate value "0.02%" is obviously wrong (and probably just a mistake in the print).

If you have questions as to which point in time this number refers to, I kindly refer you to the original paper and/or the authors.

No need to be rude. Sig figs are important, I reworded the comment a couple different ways to make the comment polite, and I’d appreciate the same courtesy. The use of an exact number for the US population is not justifiable, whether you can cite the source for it is not germane.

620 blind schizophrenics should be enough for anyone.

That sounds far more reasonable. Still, that leaves hundreds of cases that either are not being diagnosed or simply fail to exist.

Many antipsychotics are also used as anti-seizure medicines. Seizures are often induced by visual stimuli. The brain is weird.

Hearing voices in your head without having sight to confirm if anyone's actually there or not sounds actually terrifying.

What's the chance that any two low probability unrelated conditions happen to have an empty overlap at random?

I would like to hear more about that, about other mental illnesses, depression etc... Does being blind also affect these?

Congenital blind people have much higher rates of autism.

Some models of psychiatric illness view schizophrenia and autism as two broadly opposite poles of a grand spectrum, so this kind of makes sense in the context.

Do you have any further resources for this view? I'm very interested.

I have an uncle with severe schizophrenia, and a cousin with autism, and just recently noted in my journal how autism and schizophrenia seem to be the extremes of one's ability to reason about and categorize the world around them.

SlateStarCodex did a good job covering the high-level evidence for the view:


The article discusses that.

It seems intuitive to me that visual centers of the brain don't develop properly in the absence of visual stimulation. Has anybody done fMRIs to compare congenitally blind people with those who became blind later in life? Also it begs the question: which blind person with schizophrenia became blind at the youngest age?

Schizophrenia is not limited to visual hallucinations though, interesting ;o

it would be interesting to know if anyone has compared activity in visual cortex in schizophrenics having auditory vs visual vs olfactory vs tactile hallucinations to controls.

A quick search shows "hyperconnectivity" has been found betwen the amygdala and visual cortex in those with visual hallucinations.


There have been instances of blind from birth people creating great drawings. Their visual center must be working somehow to imagine and draw things they can't see.

Or they develop entirely different mechanism? I don’t see why the visual center of the brain has to be involved at all.

Because its innate

No, a big clump of neurons in that area is innate. When hooked up to functioning eyes, what we call the “visual cortex” develops in the vast majority of sighted people. If it were truly innate, babies would be born with fully functioning visual processing centers, which they are not.

There is also every reason to suspect this doesn’t happen in congenitally blind individuals, where the visual feedback loop is not available during neural development.

fair point, I think you are right. But I think that things that are innate doesn't have to be fully developed in babies. Puberty is also innate but develops in teenagers

Or that part of the brain is adapted for other uses. We cannot imagine what it's like to be congenitally blind... the world would be extremely different.

You can read Blank Slate by Steven Pinker where he talks about this. We can do neuroimaging and try to guess what happens

Marshall Mcluhan hypothesized that schizophrenia may be a consequence of literacy

Blind people can read though. Many who are born blind learn to read and type Braille. So it would have to be specifically about visual literacy?

Indeed, the written word is a purely visual medium, whereas braille is tactile

It's so refreshing to witness a succinct & perceptive thread, the tactility is the key

It may only be that what we consider to be schizophrenia in a physiologic sense presents entirely different in the blind and is unrecognizable despite being present.

Correlation doesn't mean causation.

This reminds me of a Sandra bullock movie

Not sure if this will get buried, but I have an anecdote to support the visual link, which may also help anyone dealing with psychic issues.

I was 23, living abroad, feeling totally isolated.

One day, I smoked weed which led to an "episode" I guess you could say -- quite literally I was hallucinating that I was in a hospital, while i was in my room.

What happened next was weird. I felt extremely depersonalized for weeks and months after, concurrently I developed a swirling blind spot in my right eye.

A distortion, so to speak.

I saw neurologists and was diagnosed as having an "ocular migraine" however I never had a headache so this didn't add up.

Looking back, I believe I was on the brink of becoming schizophrenic - and would have unless what happened next did.

So this next part is slightly controversial -- but hear me out

Through the several months that would follow I would discover and get obsessed with "RSD" -- a controversial company that teaches guys how to pick up girls.

On the surface, it sounds crass and not politically correct, but if you watch their videos "get you in the door" with "game", and teach you topics of incredible value, like "growth mindset", "the power of now" / meditation and believing in abundance.

Now WTF does this have to do with the topic at hand?

Well, being receptive to these new ideas and absorbing them completely changed my world view.

I grew up in an extremely liberal household, and did feel any agency to affect the world around me. Fixed mind set.

What these guys gave me was empowerment, agency, a more conservative mindset under which the world "made sense" - there was now a framework for reality, rather than chaos.

Subsequently, I was able to learn programming from scratch, start a business, go on to make 6 figures less than a year later.

Somewhere along the line the distortion and negative feeling were entirely replaced. I couldn't tell you when.

tl;dr: I was close to schizophrenia which manifested itself in visual symptoms, overcame with a mindset change

Follow up: I know it seems crazy and hate to make it political but there is data to back this up...


Try to have an open mind

Just queried my health system database and this statement as it pertains to congenital cortical blindness is factually incorrect.

Well, do explain! You can't just say something is incorrect and not elaborate.

sorry, intended to elaborate: When I query my health system's deidentified research patient data registry, there are multiple individuals with both a diagnosis of schizophrenia and a diagnosis of congenital (cortical) blindness. One can of course quibble that claims codes are unreliable (ie, these people really have different diagnoses), but my real point is that the entire article is based on a very limited analysis that could readily be refuted with any of the claims/health registry data sets.... also amusing to see this downvoted, people on HN don't like to see their pet theories questioned.

I don't think schizophrenia has any dependence on visual input at all. This is just a probability problem, since the combined probability of both occurring is very small, as the separate probabilities are already small; Anyone that has a brain can have the disease, blind or not; The disease itself is very little understood. For example, when I was a child I had visions and heard voices. I would go to sleep and then, in the middle of the night I would wake up and start seeing things around me, hundreds of voices talking, light beings, etc. Some would call me a schizophrenic, some a medium. I could be both, could be neither;

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