For those of you who have ever wondered, would Darwin take Xanax? - and I know that you're out there - there's finally an answer: no, because depression is a sign of strong evolutionary adaptation. Or something. Maybe.

According to a report discussed this week in Newsweek, depression may be an "adaptation" in human beings - and, oddly, rats - that provides for selection of stronger, fitter humans:

Writing in the journal Psychological Review, postdoctoral fellow Paul Andrews of Virginia Commonwealth University and psychiatrist J. Anderson Thomson Jr. of the University of Virginia present research suggesting that depression is present in the species, and in individuals, for a purpose, and we're playing with fire if we try to eradicate it. In evolution-speak, depression is an "adaptation," they argue. That is, it evolved because it made individuals who experienced it fitter, under natural selection, than individuals who did not experience it. Andrews and Thomson... offer as evidence the presence of a molecule in the brain called the 5HT1A receptor. This serves as a docking port for the neurochemical serotonin, which the Prozac/Zoloft/Paxil class of antidepressants targets. Human brains are not the only ones with the 5HT1A receptor. Rats also have it.

So, yeah. Darwin wouldn't want you (or, presumably, your pet rat) to pop that Zoloft, because those blues you're feeling? Are just nature's way of telling you that you need to address some issues, and you need to pay attention, lest nature weed you out. Or something. Hey, I'm not the scientist.

Why is this? Because, as Andrews and Thomson argue, "depression alters thinking and behavior in beneficial ways." For example, depressed persons are usually "highly analytical:" they "tend to ruminate, to turn an issue over and over in the mind... That can be useful, producing solutions to what tipped the person into depression in the first place, not to mention "Eureka!" moments such as discovering fire."

What they don't seem to address in any detail is how this seeming aspect of depression - heightened powers of analysis, focused thinking - is actually absent or blunted or compromised in certain depressive conditions. Women with post-partum depression might tend to ruminate more than mothers without PPD, but that rumination is also likely to be confused or even delusional. I ruminated a lot while I was struggling with PPD, but much of that rumination concerned how my baby was going to die, how I was going to die, how we were all going to die, etc, which, perhaps, might have - okay, certainly did - heighten my attention to issues like SIDS and other risks to infants, but they also made me BATSHIT CRAZY, and caused me to neglect my own health, and might have compromised my ability to mother, in the long haul, had I not medicated my way out of that obsessively ruminative state. So.

It's an interesting argument, and one that might be useful in informing how we think about certain types of depression. But we need to be careful that research like this doesn't undermine the seriousness of certain kinds of depression, nor discourage people from seeking treatment. Because - and I'd venture to guess that Darwin would agree - madly depressed mothers whose abilities to parent are compromised by, say, post-partum psychosis and the like, are very likely not useful in advancing the evolutionary advantage of the human race.

That's just a guess, though. The anti-anxiety meds that are helping me to be a calm and focused mother might have blunted my ruminatory powers.

Catherine Connors blogs at Her Bad Mother and Their Bad Mother and everywhere in between.