Six Months of Treatment for Depression: Outcome and Predictors of the Course of Illness

The goals of this study were to determine the course of illness in a cohort of depressed patients undergoing treatment for 6 months and whether there are clinically useful predictors of their course of illness.

A cohort of 175 depressed outpatients undergoing drug treatment were followed prospectively for 6 months. Patients were initially randomly assigned to fluoxetine or nortriptyline. Those who responded were encouraged to continue taking their drugs for the 6 months. Those who did not were switched to other drugs or drug combinations.

Of the 175 patients, 101 (58%) had a good outcome (achieved recovery and remained well), 54 (31%) had a fluctuating outcome (achieved recovery or remission but suffered a relapse or recurrence), and 20 (11%) had a poor outcome (remained depressed for the 6 months). Factors predicting good outcome included early response and a low level of schizoid personality disorder symptoms, and variables predicting poor outcome included a high score for harm avoidance and the absence of an early response.

Depression is a recurring and chronic disorder. Personality factors such as a high harm avoidance score and schizoid traits were associated with a worse outcome, but demographic features, depression characteristics, depression subtypes, and comorbidity were not. Early response was strongly associated with the course of illness, but none of these features added significantly to the clinicians' ability to predict outcome.