Abstract
Using the DSM‐IV criteria for personality disorders, prevalence rates for these disorders were evaluated among methadone maintenance patients, with a psychometric test—the Millon Clinical Multiaxial Inventory (MCMI‐III). We found that 77% of patients met the study criteria for at least one personality disorder. Of those who had a personality disorder, 20% had two personality disorders, 14% had three personality disorders, and 6% had four personality disorders. Rates of specific personality disorders are reported. Consistencies and divergence from existing research literature are noted. It is suggested that future research compare psychometrically based self‐report questionnaires to a structured clinical interview format, within the same clinical population.