Toward an evolutionary taxonomy of treatable conditions

The definition of disorder as a harmful dysfunction (J. C. Wakefield, 1999) is a useful concept, anchored in the recognition that the evolved human ar chitecture consists of a collection of functional mechanisms that may poten tially be impaired and whose impairment may be harmful. Because natural sel ection organized each mechanism to solve a distinct adaptive problem under ancestral conditions, the criteria for whether a mechanism is dysfunctional are supplied by whether the mechanism has become impaired in performing it s ancestral function. Because evolutionary function and dysfunction diverge markedly from normal human standards of value, many dysfunctions are benef icial, whereas various mechanisms that are performing their evolved functio n may cause disturbing outcomes. For this reason, many conditions in additi on to disorders may require treatment, and the authors attempt to sketch an evolutionary taxonomy of treatable conditions.