Objective: To evaluate the efficacy of lithium in the treatment of acute mania.
Method: Systematic overview of the literature and meta-analysis of randomised controlled trials. Estimation of (i) the differences in the reduction in mania severity scores, and (ii) the ratio and difference in improvement response rates.
Results: A total of 658 patients from 12 trials were included. Treatment periods ranged from 3 to 4 weeks. The response rate ratio for lithium against placebo was 1·95 (95%CI 1·17–3·23). The mean number needed to treat was five (95%CI 3–20). Patients were twice as likely to obtain remission with lithium than with chlorpromazine (rate ratio = 1·96, 95%CI 1·02–3·77). The mean number needed to treat was four (95%CI 3–9). Neither carbamazepine nor valproate was more effective than lithium. The response rate ratios were 1·01 (95%CI 0·54–1·88) for lithium compared to carbamazepine and 1·22 (95%CI 0·91–1·64) for lithium against valproate. Haloperidol was no better than lithium on the basis of improvement based on assessment of global severity. The differences in effects between lithium and risperidone were –2·79 (95%CI –4·22 to –1·36) in favour of risperidone with respect to symptom severity improvement and –0·76 (95%CI –1·11 to –0·41) on the basis of reduction in global severity of disease. Symptom and global severity was as well controlled with lithium as with verapamil. Lithium caused more side-effects than placebo and verapamil, but no more than carbamazepine or valproate.
Conclusion: The clinical trial evidence suggests that lithium should remain the first line treatment for acute mania.