An evolutionary approach to psychiatry

Objective: The current mainstream approach to psychiatry, characterised as empirical and phenomenological is questioned here and a new aetiological approach 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 behaviours in other species. Results: It is argued that this approach can be applied to psychiatric behaviour, 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 prominent adaptive behaviours, others represent distortions of these behaviours by a pathological process. An important line of thought in current animal behaviour research examines the concepts of self-awareness, consciousness, thought and affect in species other than man. These ideas, from an evolutionary perspective, are extended to psychiatry. A scheme illustrating this process is presented. Conclusions: We have drawn on relevant behavioural similarities between humans and other animals to show that many psychiatric states are distortions of evolved behaviour. The implications for classification, research and treatment are considerable. In particular this approach may form a bridge between fundamental research in molecular biology and the anthropomorphic approach of psychodynamics.