The Study Design:The study was multi-centered. There were 5 medical clinics in major metropolitan areas across the country that participated in this trial. Using many clinics enabled the investigators to enroll many more patients into the study and allowed for more diversity in the patients who participated. There were 3 treatment groups. Patients received either Imipramine (Imip), Lithium (Li), or a Placebo (Pl) where Imip and Li are active drugs. Patients were randomly assigned to one of the 3 treatment groups. Like most other medical studies where new, unexplored treatments are evaluated, patients chose themselves to participate in the study by signing a consent form. Patients were followed for 2-4 years to see whether or not they had a recurrence of depression. If they did not have a recurrence within this time frame, then their treatment was considered a Success. If they did have a recurrence, it was considered a Failure. The study was double-blinded. A number of additional background variables were measured for each patient.

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