Two scientists suggest that depression is not a malfunction, but a mental adaptation that brings certain cognitive advantages
Depression seems to pose an evolutionary paradox. Research in the US and other countries estimates that between 30 to 50 percent of people have met current psychiatric diagnostic criteria for major depressive disorder sometime in their lives. But 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?
[more]
Depression seems to pose an evolutionary paradox. Research in the US and other countries estimates that between 30 to 50 percent of people have met current psychiatric diagnostic criteria for major depressive disorder sometime in their lives. But 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?
[more]
Study cited in the Scientific American article above. The bright side of being blue: Depression as an adaptation for analyzing complex problems.
Depression is the primary emotional condition for which help is sought. Depressed people often report persistent rumination, which involves analysis, and complex social problems in their lives. Analysis is often a useful approach for solving complex problems, but it requires slow, sustained processing, so disruption would interfere with problem solving. The analytical rumination hypothesis proposes that depression is an evolved response to complex problems, whose function is to minimize disruption and sustain analysis of those problems by (a) giving the triggering problem prioritized access to processing resources, (b) reducing the desire to engage in distracting activities (anhedonia), and (c) producing psychomotor changes that reduce exposure to distracting stimuli. As processing resources are limited, sustained analysis of the triggering problem reduces the ability to concentrate on other things. The hypothesis is supported by evidence from many levels—genes, neurotransmitters and their receptors, neurophysiology, neuroanatomy, neuroenergetics, pharmacology, cognition, behavior, and efficacy of treatments. In addition, the hypothesis provides explanations for puzzling findings in the depression literature, challenges the belief that serotonin transmission is low in depression, and has implications for treatment. (PsycINFO Database Record (c) 2009 APA, all rights reserved) [The bright side of being blue: Depression as an adaptation for analyzing complex problems. Andrews, Paul W.; Thomson Jr., J. Anderson, Psychological Review. Vol 116(3), Jul 2009, 620-654.]



