The implicit assumption of this article is that tendency to depression is a heritable genetic trait which is preserved in the population by selection pressure.

The implicit assumption of this article is that tendency to depression is a heritable genetic trait which is preserved in the population by selection pressure. It goes on to seek an explanation for the prevalence of depression in terms of greater reproductive fitness. The risk is that by not examining this assumption, it may be laboring under a misapprehension. Depression might be a learned behavior: more "software" than "hardware." The near-total failure to validate anti-depressants as an effective treatment for depression[1] suggests that we don't have a clue as to its actual etiology. [1] E.g. http://www.independent.co.uk/life-style/health-and-families/health-news/antidepressant-drugs-udontu-work-ndash-official-study-787264.html http://www.independent.co.uk/life-style/health-and-families/... "Given these results, there seems to be little reason to prescribe antidepressant medication to any but the most severely depressed patients, unless alternative treatments have failed to provide a benefit. This study raises serious issues that need to be addressed surrounding drug licensing and how drug trial data is reported." Update after reading the whole thing: I like the practical developments this research has led to in Thomson's own practice. E.g. (page 6) “What you’re trying to do is speed along the rumination process,” Thomson says. “Once you show people the dilemma they need to solve, they almost always start feeling better.” But he seems to have really been reaching with his scientific conclusions.