“Two scientists suggest that depression is not a malfunction, but a mental adaptation that brings certain cognitive advantages”. (Scientific American) Evolutionary explanations are appealing, for if depression were not adaptive then why would it be so prevalent across cultures and epochs? Estimates are that between one quarter and one half of the public are clinically depressed at some point in their life.

The suggestion here is that the depressive state, with ruminative thinking, social isolation, and loss of interest in usually pleasurable activities, etc. promotes periods of uninterrupted analytical thinking. This turns some of the therapeutic approaches to depression on their head. Interventions which discourage ruminative thinking might prolong the resolution of a depressive episode. Patients encouraged to amplify on their ruminating, such as journalling, might do better. Perhaps even antidepressant medications might interfere in constructive problem-solving?

I have thought there might be a different evolutionary advantage to depression. After a loss or setback, the depressed person’s lack of energy, motivation and activity act to conserve resources. Their way of thinking about the world, with pessimism and a helpless sense of lack of control over what befalls one, might be more realistic, at least at such a time.