Publication bias and the pharmaceutical industry: the case of lamotrigine in bipolar disorder.

Publication bias, especially the lack of publication of negative treatment studies, is known to be a major problem in the medical literature. In particular, it appears that the pharmaceutical industry is not routinely making data from negative studies available through the published scientific literature. In this paper, we review the case of studies with lamotrigine in bipolar disorder, describing evidence of lack of efficacy in multiple mood states outside of the primary area of efficacy (prophylaxis of mood episodes). In particular, the drug has very limited, if any, efficacy in acute bipolar depression and rapid-cycling bipolar disorder, areas in which practicing clinicians, as well as some academic leaders, have supported its use. The negative unpublished data now made available on lamotrigine provide an important context for clinical practice and research, and also raise important scientific and public policy concerns about having access to studies showing inefficacy with psychotropic medications.