Stability of the MCMI among depressed psychiatric outpatients

The Millon Clinical Multiaxial Inventory (MCMI) is a promising, yet somewhat unproven psychometric inventory developed to identify clinical syndromes and personality traits consonant with the Diagnostic and Statistical Manual of Mental Disorders (3rd ed. [DSM-III]; American Psychiatric Association, 1980). The stability of its measures for both the theoretically more stable personality characteristics and the clinical syndromes was investigated in a group of depressed psychiatric outpatients. In this test-retest design with a 3-month interval between tests, clinical syndrome scales of relevance changed significantly as expected. However, many of the personality scales also changed significantly. Only four of the personality scales met a two-fold test of stability. Findings are discussed in terms of characteristics of self-report inventories such as the MCMI, the uniqueness of the depressed population, and characteristics of personality disorders.