Recovery in major depressive disorder: analysis with the life table and regression models.

Regression models and life tables were used to describe the phenomenon of recovery from major depressive disorder for 101 patients in a naturalistic study in which treatment was not controlled by the investigators. Time to recovery from the onset of the episode was protracted, as only about 50% of patients recovered by one year. Annual rates of recovery then declined steadily to 28% in the second year, 22% in the third year, and 18% in the fourth year. In contrast, speed of recovery from entry into the study was more rapid, and 63% of patients recovered by four months. The recovery rates were about 20% each month for the first four months and then declined sharply for the remaining months of the one-year follow-up. Several clinical variables were statistically significant predictors of recovery when measured from entry into the study: superimposition of the acute episode on a chronic underlying depression, acuteness of onset of he depression, and severity of depression for the subgroup of patients without superimposed illness.