An evolutionary approach to psychiatry

Objective: The current mainstream approach to psychiatry, characterised as empirical and phenomenological is questioned here and a new aetiological ap proach based on evolutionary theory is proposed. Method: A brief description of an evolutionary approach to animal behaviour is presented. The psychiatric states of anxiety, depression, 'hysterical' obsession and some aspects of psychosis are compared with related behaviour s in other species. Results: It is argued that this approach can be applied to psychiatric beha viour, that behavioural similarities exist between many psychiatric states and normal behaviour in species other than humans and many of these can be understood as adaptive. Some psychiatric states represent abnormally promin ent adaptive behaviours, others represent distortions of these behaviours b y a pathological process. An important line of thought in current animal be haviour research examines the concepts of self-awareness, consciousness, th ought and affect in species other than man. These ideas, from an evolutiona ry perspective, are extended to psychiatry. A scheme illustrating this proc ess is presented. Conclusions: We have drawn on relevant behavioural similarities between hum ans and other animals to show that many psychiatric states are distortions of evolved behaviour. The implications for classification, research and tre atment are considerable. In particular this approach may form a bridge betw een fundamental research in molecular biology and the anthropomorphic appro ach of psychodynamics.