The influence of age on the natural history of unipolar depression when treated with electroconvulsive therapy.

The influence of age on the natural history of unipolar depression when treated with electroconvulsive therapy (ECT) was studied using a naturalistic/archival study design. A sample of 125 patients who received no somatic treatment were compared with 128 patients who all received a course of ECT with at least four treatments. Patients were separated according to age at admission. Treated patients, aged 40 or older, who were clearly remitters showed no differences in previous episodes, subsequent episodes, subsequent hospitalizations, or likelihood of experiencing a period of full recovery when compared with a similar group of untreated patients. Hospitalization greater than 1 year and chronicity were significantly more common in the untreated older subjects. Treated patients aged 39 or younger, who also were clearly remitters, showed significant increases in subsequent episodes and subsequent hospitalizations when compared with a group of depressed patients of similar age who received no somatic treatment. Hospitalization greater than 1 year was also more common in the untreated younger patients. ECT clearly reduces the rate of chronicity in older patients but may be associated with an increase in episodes after treatment in the younger population.