In an era of cost containment, psychiatric drug formularies often limit choice of first-line selective serotonin reuptake inhibitors (SSRI) in the treatment of depression. OBJECTIVES: Most patients in this study belong to one of three managed care systems with varying drug formularies. The purpose of this study was to describe treatment events and utilization of services by patients with depression initially prescribed one of three SSRIs in a "treatment as usual" setting. METHODS: Patients with major depression were identified in the organization database. Retrospective chart reviews determined patient demographics, frequency of adverse events, attrition rate, and utilization of services over a six-month period following initiation of therapy. RESULTS: One-hundred forty charts were reviewed. SSRIs were equally prescribed. The mean age of patients was 39.5, (sd=14.1). Approximately 38% were Hispanic. Approximately 41% had prior SSRI therapy. Prescribers tended to follow restricted formularies, but showed no preference with an open formulary. Chi-square analyses revealed that among the SSRIs, there was no difference in attrition or in reports that patients had at least one adverse effect. On average, patients received 2.3 prescriber visits during the initial six months of therapy, with no significant difference by SSRI. CONCLUSIONS: Preliminary evidence suggests no difference in the number of outpatient prescriber visits, attrition rates, or reports of at least one adverse effect among the three SSRIs. Further analysis will examine frequency of patients who switched from initial SSRI to another antidepressant. The results of this study are limited by small sample size, non-randomization of patients, and data derived from documentation in medical records. Future research will prospectively measure symptomatology of depression, along with utilization of services, and treatment events.