Lithium treatment and prophylaxis in unipolar depression: a meta-analysis.

Meta-analysis was used to establish the efficacy of lithium in acute treatment and prophylaxis of depressive illness from existing published clinical trials. Effect sizes were measured by the odds ratio using the Mantel-Haenszel method and the Pearson product-moment correlation coefficient. Some benefit from lithium, compared with other treatments, emerged from trials of acute treatment. Lithium was clearly superior to placebo in the acute treatment of bipolar depressed patients. In controlled studies of lithium prophylaxis over five months to three years, an impressive effect was found for lithium when compared with placebo. For uncontrolled studies there was a similar-sized effect, corresponding to an improvement in the rate of favourable outcome from 35% for placebo to 70% with lithium treatment. The comparison of lithium with other antidepressants in prophylaxis showed no conclusive advantage for lithium in unipolar illness. There is no reason to doubt the efficacy of lithium in the prophylaxis of unipolar depressive illness.