DIAGNOSING COMORBIDITY IN SUBSTANCE-ABUSERS - A COMPARISON OF THE TEST-RETEST RELIABILITY OF 2 INTERVIEWS

This study examines the test-retest reliability of two interview sched ules (computer- and clinician-administered) in diagnosing lifetime com orbidity in treated substance abusers. The Computerized Diagnostic Int erview Schedule (C-DIS) and the Structured Clinical Interview for DSM- III-R (SCID) were both administered to 173 substance abusers after ran dom assignment to one of two groups. Within 1 to 2 weeks, subjects in the first group repeated the C-DIS and subjects in the second group we re reinterviewed by a different clinician, blind to the results of the initial SCID. Both instruments showed good to excellent reliability f or DSM-III-R psychoactive substance use disorders with kappas ranging from .50 to .89 for individual disorders. However, the reliability of comorbid other mental disorders was substantially poorer on both instr uments, particularly the SCID. C-DIS kappas ranged from -.05 for gener alized anxiety to .70 for simple phobia. SCID kappas ranged from .31 f or panic disorder to .83 for antisocial personality disorder. Anxiety disorders as a category, some phobic disorders, and antisocial persona lity disorder showed acceptable levels of test-retest reliability on b oth instruments. There was a trend for borderline or threshold cases t o account for some of the disagreement on the C-DIS. Differences of op inion between clinicians on organicity accounted for some of the disag reements on panic disorder and major depression. The C-DIS, unlike the SCID, tended to diagnose more disorders at initial interview, perhaps a result of its tedious probe structure. Neither instrument should be administered only once to provide a reliable lifetime diagnostic prof ile of comorbidity in substance abusers.