Publication and other reporting biases in the clinical trials literature have often been ascribed to financial vested interests from manufacturer sponsors [51]. For example, in a review [52] of all randomized controlled trials of nicotine replacement therapy (NRT) for smoking cessation, more industry-supported trials (51%) reported statistically significant results than non-industry trials (22%); this difference was unexplained by trial characteristics. Moreover, industrysupported trials indicated a larger effect of NRT (summary odds ratio 1.90, 95% CI 1.67 to 2.16) than non-industry trials (summary odds ratio 1.61, 95% CI 1.43 to 1.80). Evidence of excess significance has also been documented in trials of neuroleptics [19]. Comparisons of published results against FDA records shows that, while almost half of the trials on antidepressants for depression have negative results in the FDA records, these negative results either remain unpublished or are published with distorted reporting that shows them as positive [8]; thus, the published literature shows larger estimates of treatment effects for antidepressants than the FDA data. A similar pattern has been recorded also for trials on antipsychotics [7].
