Lithium-responsive depression

Lithium carbonate has proven effective in controlling acute mania and in reducing the frequency and severity of recurrence of both mania and depression in bipolar patients.^1-4 Several studies indicate that lithium is effective in certain unipolar depressions, but the results are inconsistent. Davis's recent review concluded that the magnitude of improvement associated with lithium was at least as great in unipolar as in bipolar depression.⁴ Mendels⁵ and Noyes et al.,⁶ using different approaches, noted that patients diagnosed as bipolar respond more frequently to lithium than do those diagnosed as unipolar. The purpose of this article is to present the problems in clarifying the kinds of depressions which do respond, and clinical guidelines for recognizing likely lithium responders.