Seven RCTs were included with 391 participants.
The combined OR for lithium versus other treatments (5 studies) was 1.14 (95% CI: 0.68, 1.91) which was not statistically significant.
For the 5 studies of lithium versus other treatments, the chi-square test was not statistically significant; the Breslow-Day statistic was 7.07, p = 0.13, df = 4; and the Zelen statistic was 0.004, p = 0.14.
One study reported on valproic acid versus placebo with an OR = 0.16 (95% CI: 0.04, 0.60).
Four studies reported on adverse events which included vomiting (lithium 25%, valproic acid 14%, and placebo 4%, p-value less than or equal to 0.05), fever (lithium 14%, valproic acid 1%, and placebo 4%, p-value less than or equal to 0.05), pain (lithium 3%, valproic acid 19%, and placebo 20%, p-value less than or equal to 0.05), twitching (lithium 8%, valproic acid 3%, and placebo 0%, p-value less than or equal to 0.05), weight gain in 27% of the lithium patients (p-value not statistically significant), hepatoxicity in 7% of the carbamazepine patients, non-compliance/toxicity in 26% of the lithium patients, sedation or fatigue (2 groups reporting 20% for valproic acid versus 4.3% placebo and 10% for valproic acid versus 0% for placebo, (p-value not statistically significant)).