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The Effectiveness of Antidepressant Monotherapy in a Naturalistic Outpatient Setting

Tih-Shih Lee, MD, PhD; Pryseley Nkouibert Assam, PhD; Kenneth R. Gersing, MD; Edwin Chan, PhD; Bruce M. Burchett, PhD, JD; Kang Sim, MBBS, MMed; Lei Feng, MB, PhD; K. Ranga Krishnan, MBChB; and A. John Rush, MD

ABSTRACT

Objective: 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.

Method: 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.

Results: 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.

Conclusions: 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.

Prim Care Companion CNS Disord 2012;14(5):doi:10.4088/PCC.12m01364

Submitted: February 14, 2012; accepted May 11, 2012.

Published online: October 4, 2012.

Corresponding author: Tih-Shih Lee, MD, PhD, Department of Psychiatry and Behavioral Science, Duke University Medical School, DUMC Box 3950, Durham, NC 27710 (tish.lee@duke.edu).