Categorical versus dimensional models of mental disorder: the taxometric evidence

OBJECTIVE: To review studies of the categorical versus dimensional status of mental disorders that employ taxometric methodology. METHOD: A comprehensive qualitative review of all published taxometric studies of psychopathology. RESULTS: Categorical and dimensional models each receive well-replicated support for some groups of mental disorders. Studies favour categorical models for melancholia, eating disorders, pathological dissociation, and schizotypal and antisocial personality disorders. Dimensional models tend to be favoured for the broad neurotic spectrum--general depression, generalized anxiety, posttraumatic stress disorder--and for borderline personality disorder. CONCLUSIONS: Taxometric research clarifies the latent structure of psychopathology in ways that have implications for the classification, assessment, explanation and conceptualization of mental disorder.