Subjects were male patients at two special British hospitals, Broadmoor and Rampton, which treat violent and dangerous persons. Personality data were obtained through the Special Hospitals Assessment of Personality and Socialization, which is an inventory of 213 questions pertaining to emotional adjustment and interpersonal behavior. Four independent groups were identified from the centroid analysis applied to test data: primary psychopath, secondary psychopath, controlled, and inhibited. The primary psychopath shows high impulsivity, aggression, moderate hostility, poor socialization, a high degree of extraversion, and an absence of social shyness. The secondary psychopath is inhibited and prone to anxiety, tension, and dysphoric mood. The controlled type manifests strong defensive denial, an absence of aggressive feelings, strong impulse control, and socialization. The inhibited type is extremely inhibited and withdrawn. Two other profile patterns were identified, but these were variants or subgroups of the secondary and controlled profile patterns. The primary and secondary psychopath patterns predominate among those having personality disorders, and controlled and inhibited patterns tend to be associated with more serious psychiatric disability. 5 tables and 37 references.