The failure of biological psychiatry to deliver on its promises of enlightening the origin of psychiatric disorders and optimizing their treatment is due to invalid theoretical postulates that derive from an outdated conceptualization of human biology. The crisis of biological psychiatry depends on its identification with functional biology. A major contribution of evolutionary biology (the other current of biological thought) is to integrate the study of environmental variables (developmental, interpersonal, and ecological) with those mechanisms that are the field of study of functional biology (genetics, anatomy, and physiology). A new theoretical framework based on the integration of functional and evolutionary explanations can revitalize the crippled field of biological psychiatry.