Linking Personality Disorders and Clinical Syndromes on the MCMI–III

We examined the relationship between personality disorders (PDs) and clinical syndromes (CSs) as measured by the Millon Clinical Multiaxial Inventory–III (MCMI–III; Millon, 1997) in a large, heterogeneous sample of psychiatric patients (N = 2,366) who completed the instrument as part of routine assessment following presentation for treatment. Using separate sets of base rate (BR) and nonoverlapping scale scores, we factor analyzed the PD and CS scales together and then separately.We correlated results from the latter analyses to determine how trait dimensions were associated with syndrome dimensions. We also studied co-occurrence at the scale level by examining CS score profiles of patients who were grouped according to their highest PD scale elevation ≥ BR75. Results for the two score sets were very similar and were consistent with previous research on the MCMI–III and its predecessors that identified 3 underlying dimensions loading both PD and CS scales. Three fourths (76.2%) of the sample had a highest PD scale ≥ BR75, and among these, 90% had at least 1 CS scale ≥ BR75, whereas 62.4% had 3 or more CS scales above this elevation. Findings underscore the substantial overlap between PDs and CSs along 3 dimensions that resemble Horney’s (1945) tripartite interpersonal distinction of moving toward, away, and against, as well as Eysenck’s (1994) higher order factors of neuroticism, extraversion, and psychoticism.