Lithium potentiation of antidepressant treatment.

The addition of lithium carbonate to an antidepressant drug regimen in depressed patients initially unresponsive to the antidepressants alone has been reported to bring about rapid improvement in the majority of these individuals. Nine additional cases are reported in this article. The response to lithium addition was more variable than described previously. Two patients showed sustained improvement, two showed transient improvement but then relapsed, two other cases with bipolar histories became manic, and three did not respond at all. Possible reasons for this variability are discussed.