[The pharmacological treatment of bipolar disorder: a systematic and critical review of the methodological aspects of modern clinical trials].

OBJECTIVE: To review systematically the main clinical trials on the pharmacological treatment of bipolar disorder and to make a critical analysis of their methodological aspects.
METHOD: A search in Medline, ISI and PsycINFO databases was conducted, using the following search terms: "bipolar", "randomized", "placebo" e "controlled". Randomized, double-blind, placebo-controlled clinical trials on the pharmacological treatment of bipolar disorder were selected. Besides, according to our criteria, samples had to consist of at least 100 patients and experimental drug had to be used as monotherapy.
RESULTS: 34 articles met our selection criteria. All drugs currently indicated for mania, bipolar depression and maintenance treatment of bipolar disorder were more effective than placebo in at least one clinical trial. However, these studies had highly selected samples, high dropout rates and low response rates.
CONCLUSION: Modern clinical trials on pharmacological treatment of bipolar disorder have important methodological limitations. So, their results should be taken with caution.