• 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 the depression, and severity of depression for the subgroup of patients without superimposed illness.
Keller MB, Shapiro RW, Lavori PW, Wolfe N. Recovery in Major Depressive DisorderAnalysis With the Life Table and Regression Models. Arch Gen Psychiatry. 1982;39(8):905-910. doi:10.1001/archpsyc.1982.04290080025004