Reliability of personality disorder symptoms and personality traits in substance-dependent inpatients

The authors compared the internal consistency, 1-year temporal stability, and self-informant agreement of ratings of personality trait (NEO Five-Factor Inventory; NEO-FFI; P. T. Costa & R. R. McCrae, 1992) and personality disorder symptom severity (Structured Clinical Interview for DSM-III-R Personality Disorders Questionnaire; SCID-II-Q; R. L. Spitzer, J. B. W. Williams, M. Gibbon, & M. First, 1990) in 131 substance-dependent inpatients. Internal consistency coefficients were acceptable to very good for most NEO-FFI and SCID-II-Q scales, and temporal stability correlations were significant for all measures. Agreement between patient and informant ratings was more modest. Substance abuse and depression symptom severity moderated the temporal stability and self-informant agreement of several personality trait and disorder ratings. The authors did not find that the five factors were more reliable than the Axis II symptoms. Issues related to the reliability of personality assessment in multiply diagnosed patients are discussed.