Evaluation of the adequacy of outpatient antidepressant treatment

Objective: Most studies evaluating the adequacy of antidepressant treatment have focused on the relatively small segment of the medicated population with a diagnosis of depression. This study assessed the rates and determinants of the adequacy of antidepressant treatment among all outpatients who receive antidepressants. Methods: A retrospective analysis was conducted using pharmacy claims made by patients with a primary care physician in a managed care plan at an academic medical center from 1996 through 1999. Adequate antidepressant treatment was defined as prescription of the lowest likely effective dosage of an antidepressant for at least 90 consecutive days. Data for a total of 15,476 records and 1,550 patients were available. Results: Overall, 46 percent of the patients receiving antidepressants received minimally adequate treatment. The rates of adequate treatment were significantly higher among patients whose antidepressant prescriptions were written by both primary care physicians and psychiatrists than among patients whose antidepressants were prescribed solely by primary care physicians (61 percent versus 31 percent). Patients who had trials of SSRIs had significantly higher rates of treatment adequacy than those who had trials of tricyclic antidepressants but not SSRIs (51 percent compared with 27 percent) or trials with other antidepressants only (24 percent). Conclusions: Pharmacy claims from all patients receiving antidepressants indicate that these drugs are prescribed in ways that are unlikely to be fully effective across the broad spectrum of patients. Adequate antidepressant treatment trials were most likely when psychiatrists collaborated with primary care physicians or other specialists and when SSRIs were used.