Institute For The Future

Does Depression Serve a Purpose?

Depression, the mental health variety, doesn't seem to make a whole lot of sense, at least from an evolutionary perspective. Lots of people are depressed--as many as 50 percent, according to some high-end estimates--and it strikes across age and cultures, making depression appear to be some fundamental part of human genetics rather than a quirk of urban living, say. As Paul Andrews and J Anderson Thomson point out, "the brain plays crucial roles in promoting survival and reproduction, so the pressures of evolution should have left our brains resistant to such high rates of malfunction. Mental disorders should generally be rare — why isn’t depression?"

Andrews and Thomson suggest that in light of this, depression isn't "a disorder at all" but is "in fact, an adaptation...which brings real costs, but also brings real benefits." Noting the real problems with depression--lethargy, difficulty concentrating, even suicide--they suggest that bouts of depression help people gain perspective through the ways in which negative feelings facilitate analytic thinking. People who are depressed tend to focus intensely on the problems at hand and break them into smaller analytic chunks--in effect, depressive feelings enhance our problem solving skills to the point that "people who get more depressed while they are working on complex problems in an intelligence test tend to score higher on the test."

This sort of thinking--uninterrupted, intense problem solving--requires huge amounts of mental energy, and as a result:

 

Many other symptoms of depression make sense in light of the idea that analysis must be uninterrupted. The desire for social isolation, for instance, helps the depressed person avoid situations that would require thinking about other things. Similarly, the inability to derive pleasure from sex or other activities prevents the depressed person from engaging in activities that could distract him or her from the problem. Even the loss of appetite often seen in depression could be viewed as promoting analysis because chewing and other oral activity interferes with the brain’s ability to process information.

 

Andrews and Thomson's point isn't to deny the significant psychological toll of depression--but to suggest that viewing depression as serving a productive purpose, even a potentially dangerous and debilitating one, can help mental health practitioners flip the challenge of depression into something that patients can harness in a useful way.