

Blood Tests Can Accurately Diagnose Depression - MRonney
http://www.theatlantic.com/health/archive/2012/02/study-of-the-day-blood-tests-can-accurately-diagnose-depression/252664/

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aidenn0
Just some quick math:

8% False-negative rate 19% False-positive rate In a given year ~7% of all
people will have major depressive disorder at some point so if we gave this
test to random people 75% of the people who test positive are healthy.

So this clearly isn't a useful test as a first screening. If, however, someone
is showing symptoms of MDD, it could be useful as a test there, as they are in
a population with fewer healthy people.

In any event the article in the Atlantic (I don't have a subscription to
nature) talks about using it for a completely different reason: Given someone
already diagnosed with MDD, administer the test. With 92% chance it will come
back positive, and you can say "See, there is something _physically_ wrong
with you, and you need treatment." That does seem like a good use for it.

~~~
DanBC
I know this isn't your intent, but...

> _"See, there is something physically wrong with you, and you need
> treatment."_

...could be a pretty stigmatising way to talk about mental health problems. I
know you're not saying that people with minor depression are "making it up";
but I feel the need to say that an illness doesn't need to be 'physical' to be
real.

Sorry for the slight de-rail.

~~~
Locke1689
In order to be treated via medication there certainly must be something
physically wrong with the patient. I don't believe that the parent is
referring to all categories of mental illness, only ones which can be treated
by medication. If you're talking to a physician and there's nothing physically
wrong with you, you're in the wrong room.

~~~
DanBC
See, for example, the serotonin hypothesis, and the fact that good quality
evidence shows that for mild to moderate depression CBT is more effective than
SSRIs.

I was careful to put a bunch of qualifiers in my post, but i'm keen to make
sure people realise that mental health problems can be very serious even if
they're not "physical".

This is important because people with chronic fatigue are often sent to see
CBT practitioners. Lots of those people feel that they're being trivialised or
fobbed off; they say things like "I have a real illness".

It's a shame, because CBT is used to reduce pain in cancer patients, and
there's reasonable evidence that it's useful in CFS/ME type illnesses.

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tokenadult
This start-class Wikipedia article

<http://en.wikipedia.org/wiki/Sensitivity_and_specificity>

discusses some of the issues around "sensitivity" of a test (the tendency not
to have false negatives) versus "selectivity" of a test (the tendency not to
have false positives). And of course what level of each to trade off for in a
particular medical situation depends on the seriousness of the disease, the
selectivity and sensitivity of other kinds of testing, and what happens to a
patient if a true case is missed or if the patient gains a false diagnosis of
having the disease.

I'd definitely like to see the approach mentioned in the study

[http://www.nature.com/mp/journal/vaop/ncurrent/full/mp201116...](http://www.nature.com/mp/journal/vaop/ncurrent/full/mp2011166a.html)

replicated by other researchers

<http://norvig.com/experiment-design.html>

before figuring that blood tests will replace patient mood self-rating scales
for diagnosing depression, but this is an interesting approach. And perhaps
identifying reliable biomarkers for depression will suggest new treatment
approaches.

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jobu
In case anyone else is wondering, here's what they tested:

 _" Serum levels of nine biomarkers (alpha1 antitrypsin, apolipoprotein CIII,
brain-derived neurotrophic factor, cortisol, epidermal growth factor,
myeloperoxidase, prolactin, resistin and soluble tumor necrosis factor alpha
receptor type II) in peripheral blood were measured ..."_

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RyanMcGreal
Conclusion: eight members of the control group now wondering if they're
actually depressed and just didn't know it.

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hack_edu
One has to wonder what types or levels of depression this claims to validate.
Depression can be caused by a lot more than simply down times or highly
impactful life events. The brain and mind are so unbelievably mutable and
plastic that I cannot possibly imagine how this could hold up to a
realistically sized test group; this study followed less than 100 patients...

If this test can't detect depression in, say Bipolar patients, can it really
claim to detect depression?

~~~
sophacles
Is bipolar depression the same as clinical depression? Are there actually many
different things currently lumped under depression? I honestly don't know, but
I think at least the first answer is "no". At the very least, if this test can
be refined to reliably catch some types of depression, it can be used as a
confirmation to those diagnoses, and further, help narrow down useful med,
known to work well with those who suffer and who have symptoms including this
positive blood test.

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xenophanes
My comments:

[http://groups.google.com/group/beginning-of-
infinity/browse_...](http://groups.google.com/group/beginning-of-
infinity/browse_thread/thread/34b04b481e3ec267)

------
maeon3
People seem to treat depression as a disease or illness to be medicated away
asap. Depression is your body's way to get you to stop interacting with the
others and make some serious changes in your life to fix the damn problem.
Depression is part of all socities and many mammal species. Depressed people
are found to be more rational than the people who feel successful. We've
become a society obsessed with constant happiness. Well you know what?
Sometimes life sucks and your brain is going to continually kick you while you
are down until you get up and fix your problem.

I guess its good for big pharma sales babes. Doctors don't even know why these
drugs work. "Diagnose depression??" It's like diagnosing a air conditioner
that comes on when it gets hot inside. The air conditioner isn't the problem
to be removed. Depression is part of what it means to be human and enlightened
people pull out the power tools and make the appropriate changes to re
evaluate what we should be doing now.

~~~
ryusage
Your description of depression makes it sound like, if only depressed people
would stop taking medication, they would naturally find the "actual problem"
(which you assume exists), solve it, and then no longer be depressed.

I don't know how much experience you've had with actual clinical depression,
but as far as I've seen, those people are not "more rational", and leaving
them to their own devices makes things worse, not better.

~~~
maeon3
I've studied the matter in depth, ive tried to talk sense into someone ready
to jump off a 4 story building onto concrete or drive into water with
handcuffs on the wheel. I was unable to fix them. I left this guy to his own
devices when nothing I did helped, I said your brain has some destructive
feedback loops going on and you need to go and fix it. He's alive today. Im no
expert but I sure have opinions!

