Determinants of Antidepressant Treatment Outcome

OBJECTIVE: To understand the determinants of the outcome of an episode of major depression, including factors that affect receipt of guideline-consistent care and their subsequent effect on treatment outcomes, particularly relapse or recurrence. Results of previous studies are generalized to a population typical of depressed individuals in the United States, i.e., a cohort of antidepressant users with employer-provided health benefits. STUDY DESIGN: A quasi-experimental design was used to assess the determinants of the outcome of an episode of major depression. Healthcare utilization-based measures of treatment characteristics and outcomes were used. PATIENTS AND METHODS: The final analytical file for this study contained data on 2917 patients who had an antidepressant prescription associated with an indicator of a depressive disorder. The authors identified relapse or recurrence of depression by (1) a new episode of antidepressant therapy, (2) suicide attempt, (3) psychiatric hospitalization, (4) mental health-related emergency department visits, or (5) electroconvulsive therapy. Antidepressant use patterns were used to construct a measure for adherence to treatment guidelines. Multivariate Cox proportional hazard and logit regression models were used to predict relapse/recurrence and adherence with treatment guidelines, respectively, for each patient. RESULTS: Factors that affect relapse/recurrence include comorbidities, demographics, and adherence to treatment guidelines. Factors that affect adherence to treatment guidelines include choice of initial antidepressant drug, comorbidities, psychotherapy, and frequency of physician visits. CONCLUSIONS: Adherence to treatment guidelines was associated with a significant reduction in the likelihood of relapse or recurrence of depression. Choice of initial antidepressant drug affects adherence to treatment guidelines.