

Lack of vitamin D possible cause of schizophrenia - adammichaelc
http://www.thestar.com/article/858836--lack-of-vitamin-d-cause-of-schizophrenia-study

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adammichaelc
Quote that sums up the article:

 _The study, published this week in the journal Archives of General
Psychiatry, used Denmark’s blood bank, which contains samples from almost
every baby born in the country since 1982. It compared the blood of 424 people
who developed schizophrenia to an equal number of those who did not.

The lead author, renowned schizophrenia researcher John McGrath, found that
babies with a low level of the vitamin during fetal development and infancy
had nearly two times the chance of developing the disease._

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carbocation
Thanks for the quote. There is a bit of correlation-causation concern here.
For example, it is possible that whatever causes the decreased Vitamin D also
causes schizophrenia. It need not be some chemical, either; it could be tied
to behavioral or even genetic problems. For example (no truth to this that I
know of but for sake of discussion): "Parents with a genetic predisposition to
schizophrenia have tendencies that make them are less likely to provide proper
nutrition or typical sun exposure to their children. Thus, those with a
genetic predisposition for schizophrenia also have lower vitamin D, though
that is entirely outside the causal chain." That (made-up) hypothesis would
fit just as well as the "Vitamin D is in the causal chain" hypothesis, no?

Given the uncertainty--and the suggestive epidemiological associations--this
seems like an excellent subject for a clinical trial. I seem to recall that
one is actually occurring (though perhaps for a different disease), but I
can't find the link.

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hugh3
We're still talking about awfully low levels. Schizophrenia is a rare
condition, and doubling your chances of getting a rare condition still leaves
it as a rare condition. When a risk factor for a rare disease merely increases
the risk by a factor of two it's usually not worth worrying too much about,
and it'll probably remain too difficult to sort out the cause-and-effect.

And yet, I can guarantee that many people reading this article will
immediately take it to heart that "not getting enough sun during pregnancy
causes schizophrenia" and make it a part of their personal belief structure.
Perhaps the worst effects will be on the mother of schizophrenics, who having
just got over the Freudian hangover in which all mental illnesses are blamed
on the failings of the parents, will now be able to blame themselves for
wearing too much sunscreen during pregnancy.

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car
_Schizophrenia is a rare condition_

Schizophrenia is actually a common disease, affecting ~1% of the world
population, regardless of ethnicity.

~~~
carbocation
What you say is in agreement with the common wisdom. However, I'll offer two
caveats:

It may be no more than a myth that schizophrenia affects all ethnicities
equally, according to a review of the data:
[http://schizophreniabulletin.oxfordjournals.org/content/32/1...](http://schizophreniabulletin.oxfordjournals.org/content/32/1/195.full)

According to a systematic review, it appears that ~0.4% of the world
population is affected (lifetime prevalence), not 1%:
<http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1140960/>

At any rate, I don't disagree with your general points, I just thought you
might be interested in the above refinements.

~~~
car
Thank you for making this more specific. I checked on Wikipedia after my
comment, and found what you cite. So common wisdom needs to adapt.

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car
Theories about the etiology of schizophrenia are a dime a dozen. I did my
thesis on the genetics of schizophrenia 20 years ago, and to this day nothing
has come of it.

If the research cited is not in one of the top journals, I'd not even bother
reading the abstract.

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AndrewDucker
Does "The Archives of General Psychiatry" count as one of the top journals?

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car
To me that would be Science, Nature, Cell, not necessarily in this order.

These journals have the highest impact factor, which is "sort of like
PageRank". You could compare this to the IF of the mentioned journal.

~~~
AndrewDucker
It is the psychiatric journal with the highest impact factor, considered a
flagship of psychiatric research.

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reader5000
Society greatly underestimates the surprising pyschotropic efficacy of common
foods and nutrients.

~~~
hugh3
Let me guess. Your source for that would be a diet book written by some guy
who spends half the book complaining that his theories are being dismissed by
mainstream science?

