THE EFFECTS OF SUBSTANCE USE DISORDER ON THE CLINICAL PRESENTATION OFANXIETY AND DEPRESSION IN AN OUTPATIENT PSYCHIATRIC CLINIC

Background: The comorbidity of substance abuse or dependence and psych iatric illness can complicate the diagnosis, clinical course, and trea tment of dually diagnosed patients. In this study, we examined the rel ationship between substance use disorder (SUD) and psychopathology in an outpatient psychiatric setting. Method: Among 391 patients evaluate d at an anxiety and affective disorders clinic, 54 patients met DSM-II I-R criteria for lifetime substance use disorder and current unipolar depression or anxiety disorder. We selected 54 sex- and age-matched co ntrols with psychiatric illness without SUD as a comparison group, All patients were given a structured diagnostic interview and symptom rat ing scales. In addition to comparing dual and single diagnosis groups, we compared those within the dual diagnosis group and those with prim ary psychiatric disorder with those with primary SUD; we also compared those with current versus past SUD. Results: In contrast to findings in other settings, there were no significant differences in the severi ty of psychopathology between patients with and without substance abus e/dependence. Within dually diagnosed patients, those with primary men tal disorder were more anxious and depressed than those with primary S UD, Patients with primary mental disorder had a significantly higher n umber of psychiatric diagnoses, an earlier onset of any psychiatric di sorder, and were more likely to have received treatment. Conversely, p atients with primary SUD had a higher number of substance use disorder diagnoses and an earlier onset of SUD. Conclusion: Dually diagnosed p atients had the same degree of psychopathology as patients with only p sychiatric disorders in this outpatient psychiatric population. The pr imary/secondary classification may be useful to distinguish between su bgroups of dual diagnosis patients, Future studies are necessary to de termine if this distinction can be useful to predict course and outcom e in dually diagnosed patients.