The long-term course of depression in patients who present for treatment carries prognostic and therapeutic implications. This study presents prospective data on the time to recovery from an episode of major depressive disorder of 5 years' duration among patients followed up since 1978 in the National Institutes of Mental Health Collaborative Program on the Psychobiology of Depression.
Survival analysis was used to examine the 10-year course of the 431 probands with major depressive disorder with a specific focus on the 35 probands who were observed to be continuously ill for the first 5 years. Univariate analytic techniques were used to describe the demographic and clinical variables in the group that recovered and the group that did not. By study design, somatic treatment was assessed but not controlled by the investigators.
By year 10,93% (Kaplan-Meier estimate) of probands had recovered from their intake episode of major depressive disorder. In those ill for the first 5 years, 38% had recovered within the next 5 years. Shorter duration of illness prior to intake and being married were associated with the group that recovered. Pharmacological treatment dosages averaged 100 mg of imipramine hydrochloride equivalent in the chronically ill group.
Despite lengthy periods of illness, people continued to recover from major depressive disorder for up to 10 years of prospective follow-up. Few demographic and clinical variables distinguished those who recovered from those who did not. Treatment, as observed in this naturalistic study, was at a low level despite lengthy illness.