Personality disorders in substance abusers: relation to substance use.

Previous studies have documented high but variable rates of DSM personality disorders (axis II) in clinical samples of substance abusers. Distinguishing between personality disorder symptoms that are independent versus substance-related (SR) is a particular challenge for diagnosing comorbid axis II disorders in substance abusers. DSM-IV guidelines currently recommend excluding axis II symptoms that are accounted for by an axis I disorder, including a substance use disorder. In this study, axis II diagnoses were made on a heterogenous clinical sample of 370 patients entering treatment for substance use disorders. Axis II diagnoses were made according to DSM-III-R criteria using the Structured Clinical Interview for DSM-III-R (SCID-II), which was modified to determine, on an item-by-item basis, whether symptoms were attributed to subjects' substance use disorders or independent of these disorders. The majority (57.0%) of substance use disorder patients met criteria for at least one comorbid axis II disorder, with cluster B (45.7%) being particularly prominent, especially antisocial personality disorder (ASP) (27.0%) and borderline personality disorder (BPD) (18.4%). Notably, inclusion of SR symptoms led to a substantial number of newly diagnosed cases, especially for ASP (19.2%) and BPD (11.4%). Including SR symptoms improved the reliability of ASP and did not change the reliability of BPD diagnoses. Generally, patients with SR and independent personality disorders had a similar clinical profile.