Evolutionary biology: a basic science for psychiatry?

Evolutionary biology has much to offer psychiatry. It distinguishes between ultimate and proximate explanations of behavior and addresses the functional significance of behavior. Subtheories, frequently voiced misconceptions, specific applications, testable hypotheses and limitations of evolutionary theory are reviewed. An evolutionary perspective is likely to improve understanding of psychopathology, refocus some clinical research, influence treatment and help integrate seemingly unrelated findings and theoretical explanations.