A psychometric study of the prevalence of DSM-IV personality disorders among office-based methadone maintenance patients.

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.