The authors of this paper do not have any commercial associations that might pose a conflict of interest in connection with this manuscript.
Magnitude of effect of lithium in short-term efficacy studies of moderate to severe manic episode
Article first published online: 7 DEC 2007
Volume 9, Issue 8, pages 793–798, December 2007
How to Cite
Storosum, J. G., Wohlfarth, T., Schene, A., Elferink, A., Van Zwieten, B. J. and Brink, W. v. d. (2007), Magnitude of effect of lithium in short-term efficacy studies of moderate to severe manic episode. Bipolar Disorders, 9: 793–798. doi: 10.1111/j.1399-5618.2007.00445.x
- Issue published online: 7 DEC 2007
- Article first published online: 7 DEC 2007
- Received 26 April 2006, revised and accepted for publication 21 September 2006
- manic episode;
- short-term treatment
Objectives: To provide an accurate estimation of the magnitude of effect of lithium in short-term efficacy studies conducted in patients with moderate to severe manic episode.
Methods: All placebo-controlled randomized studies submitted to the Medicines Evaluation Board (MEB) in which lithium was used as the third study arm were selected for the meta-analysis. The studies were part of registration files submitted to the MEB between the years 1997 and 2005. In addition, Medline and EMbase searches were conducted with the key words ‘manic’ (‘mania’ for the EMbase search) and ‘placebo’ in order to identify additional placebo-controlled studies of lithium. This search was updated until March 1, 2006. Two effect size indicators were used based on the primary outcome measure of each study: Cohen's standardized effect size based on the difference in mean change from baseline, and numbers needed to treat (NNT) based on the difference in treatment response defined as ≥50% improvement from baseline on day 21.
Results: Six studies were identified. They involved a combined total of 470 patients in the lithium groups and 562 in the placebo groups. The overall standardized effect size was 0.40 [95% confidence interval (CI): 0.28, 0.53] and the overall NNT for response was 6 (95% CI: 4, 13). In the placebo groups response rates varied from 21% to 47%.
Conclusions: The results indicate that lithium is an effective drug in the treatment of moderate to severe manic episode. The variability in placebo response indicates that a placebo control arm in efficacy studies among patients with moderate to severe manic episode is necessary.