Blood Test for MDD

[themind]

http://www.eurekalert.org/pub_releases/200...a-urm030608.php

We are living in an interesting time to be mentally interesting!

[~nestling~]

You mean we don't know we're depressed and they have to check our blood to find out??!!!!

[rowen]

You mean we don't know we're depressed and they have to check our blood to find out??!!!!

Of course we know. It's everyone else who doesn't get it.

[resonance]

That article is misleading...

From the link, here's the description of the study:

In their study, Rasenick and colleagues compared brain samples from depressed people who had committed suicide with controls who had no history of psychiatric disorders.

It's not a blood test used for diagnosis, but a research technique performed on brain tissues from dead people.

The research compares brain tissues from depressed-people-who-killed-themselves (not depressed people in general, who have by definition been differently affected by depression on account of not having killed themselves), and controls. If this test were a diagnostic test, it would not be very interesting since we wouldn't know from the results whether the brain tissue we were testing came from someone who was depressed or not; we might get identical results from someone who was depressed but not suicidally so as we would from someone who was happy as a clam. Or we might not. We don't know.

And it isn't even a diagnostic test. The researchers weren't testing to see whether a given slice of brain tissue belonged to someone from the suicided group or the control group, they were testing to see whether overall there were specific chemical differences between one group and the other. You can have an overall group difference that doesn't hold true for all of the people in each group (for example, men are on average taller than women but there are still a number of women who are taller than the average man).

Even if this turned out to be a tool that reliably discriminates brain tissue of suicides from brain tissue of controls, it takes a while and has only been done on dead people. We have screening and diagnostic techniques right now that are fast, cheap, pretty accurate, and do not require you to be dead.

What I've described above probably much more accurately represents what the scientist told the journalist, than what the journalist printed. I feel kind of bad for him; everyone I knew in academia while I was in a phd program there had stories about their research being horribly misrepresented in mainstream media.