Episode recurrence in bipolar disorder following discontinuation of stable maintenance treatment with lithium salts was analyzed from 14 studies involving 257 patients with bipolar I disorder. More than 50% of new episodes of illness occurred within 10 weeks of stopping an average of 30 months of treatment. By survival analysis of 124 cases in which the time to a new episode was known, the computed time to 50% failure of remission was 5.0 months after stopping therapy; the time to 25% recurrence of mania was 5.2 times earlier than for depression (2.7 vs 14 months). In 16 patients with a mean cycle length before treatment of 11.6 months, the time to a new episode when off lithium therapy was only 1.7 months. Risk of early recurrence of bipolar illness, especially of mania, evidently is increased following discontinuation of lithium use and may exceed that predicted by the course of the untreated disorder. The basis and management of risks associated with discontinuing effective long-term mood-stabilizing treatment require further study.