Evolutionary theory and the treatment of depression: It is all about the squids and the sea bass.

According to the analytical rumination hypothesis, depression is an evolved adaptation (like pain or anxiety) that served in our ancestral past to keep people focused on complex interpersonal problems until they could arrive at a resolution (spontaneous remission). If this is true, then those clinical treatments that most facilitate the functions that depression evolved to serve are likely to be more advantageous in the long run than others that simply relieve distress. For example, antidepressant medications may be efficacious in the treatment of depression but only work for so long as they are taken. They may also have an iatrogenic effect that prolongs the duration of the underlying episode. Cognitive and behavioral interventions are as efficacious as medications in terms of reducing acute distress and also appear to have an enduring effect that protects against the return of subsequent symptoms. However, the bulk of the evidence for this effect comes from comparisons to prior medication treatment and it remains unclear whether these psychosocial interventions are truly preventative, or antidepressant medications iatrogenic. A study is described that could resolve this issue and test evolutionary theory with respect to the purported role of rumination in bringing about spontaneous remission.