Reliability and validity of the structured interview for personality disorders in adolescents.

The Structured Interview for the DSM-III Personality Disorders was administered to 23 currently affectively ill adolescents and their parents. Interviews were videotaped and rerated; interrater agreement was moderate (weighted K = 0.49; unweighted K = 0.59). Moreover, there was evidence of convergent validity for Cluster II traits and disorders (borderline, histrionic, narcissistic), insofar as these diagnoses were associated with higher scores on the novelty-seeking subscale of the Tridimensional Personality Questionnaire as predicted. Cluster II patients tended to have higher rates of attention deficit disorder and bipolar disorder, and higher rates of suicidal gestures among second-degree relatives. Some difficulty was encountered differentiating symptoms of affective illness from those of personality disorder and in deciding when personality traits were impairing enough to call them disorders. Reliability may be improved by: (1) interviewing patients when out of affective episode; and (2) using standardized functional impairment criteria for differentiating personality style from disorder. Additional work is advocated to learn if personality disorders are precursors, epiphenomena, or the consequences of affective disorder.