After lithium augmentation: a retrospective follow-up of patients with antidepressant-refractory depression.

There have been no systematic follow-up studies of depressed patients with documented refractoriness to antidepressants treated with lithium augmentation. To assess their longitudinal course, 66 (88%) of an original cohort of 75 such patients were followed in a retrospective, naturalistic design for 29.0 +/- SD 15.3 months. At follow-up, 29% had poor, 23% fair, and 48% good outcomes. An acute marked positive response to lithium augmentation predicted a good subsequent course. Acute partial and non-responders had a less benign outcome despite subsequent treatments. These findings indicate that outcomes of patients with documented refractory depression are heterogeneous. There is a suggestion that an acute marked response to lithium augmentation is sustained regardless of the duration of taking lithium, but this must be regarded as speculative.