Attainment and maintenance of reliability of axis I and II disorders over the course of a longitudinal study

The baseline interrater reliability, test-retest reliability, follow-up interrater reliability, and follow-up longitudinal reliability of axis I and axis II diagnoses were assessed using the Structured Clinical Interview for DSM-III-R Axis I Disorders (SCID-I) and the Diagnostic Interview for DSM-III-R Personality Disorders (DIPD-R). Excellent kappas (>.75) were found in each of these reliability substudies for the majority of axis II disorders diagnosed five times or more. Dimensional reliability figures for axis II diagnoses were generally somewhat higher than those for their categorical counterparts; most intraclass correlation coefficients (ICCs) were in the excellent range. Excellent kappas were also found in each of these four reliability substudies for over half of the axis I disorders diagnosed five times or more. Taken together, the results of this study suggest that the reliability of axis II disorders is both good to excellent and practically equivalent to that found for most axis I disorders. The results of this study also suggest that high levels of reliability, once achieved, can be maintained over time for both axis I and II disorders.