Thanks.
It's my belief that what a person with depression should do is to try various treatments and see what works. Since we don't yet have any test to predict responsiveness to treatments based on a person's genetic makeup, all we can do is gamble, do what works, and throw out anything that doesn't.
For my part, I should also try eating healthier, exercising, and other lifestyle changes. But the Wellbutrin I'm now on has definitely helped pull me out of some really dark holes, for three different depressive episodes, most recently in the first half of 2011. Prozac, on the other hand, was worse than useless.
I think it will all boil down to interactions between genetics and environment. I suspect there are a number of genes that all correlate with higher risk of depression, and depression associated with some of these genes (and combinations thereof) respond strongly to environmental pressures, while others do not show as strong a response. It's encouraging that people are beginning to unravel this sort of thing though, as your article points out with one particular gene.
It is known that depression rates have increased over the past few decades - whether because of increased diagnosis or increased incidence isn't known. However, depression certainly existed in historical times - many famous artists showed telltale signs of it, and it is easy to find writings about "melancholy" and such from the 19th century. As for why it evolved, there are some evolutionary psychology explanations. But I don't put much stock in that whole field - it's full of plausible explanations made up on the spot without any way of testing their conclusions.
