The Structured Clinical Interview for DSM-III-R, Axis II and the Millon Clinical Multiaxial Inventory: A concurrent validity study of personality disorders among anxious outpatients

The purpose of this study was to examine the concurrent validity of personality disorder diagnoses and the interrater reliability of a relatively new instrument for assessment of personality disorders, the Structured Clinical Interview for DSM-III-R, Axis II (SCID-II). Diagnoses of agoraphobic outpatients yielded by a standardized interview (SCID-II) and by a self- report questionnaire (Millon Clinical Multiaxial Inventory, MCMI-II) were compared. The interrater reliability coefficients for the SCID-II with a sample of anxious outpatients were promising: The kappa coefficient for presence or absence of any personality disorder with the SCID-II was .75; for individual personality disorder categories, reliability coefficients ranged from .61 to .81 (median κ = .67), with the highest reliability obtained for avoidant personality disorder (κ = .81). Agreement between the two instruments was poor to moderate regardless of the criterion set for a diagnosis of personality disorder on the MCMI. Kappas for presence/absence of any personality disorder ranged from .20 to .28. The concurrent validity coefficients for individual disorders or clusters ranged from .06 to .52. These results are congruent with other investigations showing disturbingly little convergence across various instruments for assessment of personality disorders.