The Effectiveness of Antidepressant Monotherapy in a Naturalistic Outpatient Setting

Abstract

To assess a representative sample of clinically depressed outpatients during acute treatment with antidepressant medication monotherapy to determine clinical outcomes and evaluate relationships between outcomes and selected baseline/treatment features. This naturalistic study examined data on outpatients at the Department of Psychiatry, Duke University Medical Center, Durham, North Carolina, from January 2000 through December 2010. Eligible patients (N = 1,722) had a diagnosis of clinical depression (major depressive disorder, dysthymic disorder, or depressive disorder not otherwise specified as defined in DSM-IV-TR). Sociodemographic/clinical data were gathered at study entry (date of first treatment). The Clinical Global Impressions-improvement (CGI-I) and -severity of illness (CGI-S) scales were administered at entry and at study exit (end of follow-up) after 1 to 9 weeks of treatment. Analysis of variance, F tests, and t tests determined relationships between outcomes and treatment duration, baseline severity, and sociodemographic/clinical features. Thirty-nine percent of participants reported substantial improvement (CGI-I score = 1 or 2) from entry to exit, 33% reported minimal improvement (CGI-I score = 3), 22% reported no change, and approximately 7% reported worsened illness. Greater improvement (CGI-I score) and greater reduction in depressive severity (CGI-S score) were associated with greater baseline depressive severity and longer treatment duration (all P < .001). Participants with greater baseline depressive severity experienced larger reductions in depressive severity but reported worse CGI-I scores at exit. Less improvement in CGI-I scores was seen in women compared to men (P = .018). Less improvement in CGI-I scores and less reduction in CGI-S scores were seen in participants ≤ 60 years of age (P = .040 and P = .025, respectively) and those with comorbid substance abuse (P < .001 and P = .010, respectively) or anxiety (P = .018 and P < .001, respectively) disorders. Most depressive symptom improvement occurred within the first 4 to 6 weeks of antidepressant monotherapy. Greater baseline severity, comorbid substance abuse, and comorbid anxiety disorders are associated with worse outcomes.