One criticism of the 5-HTTLPR-stress studies published to date is that investigators often performed multiple tests, using different subsets of their population or different stress or depression measures, but focus their paper on the tests that produced the most significant results and present their overall findings as a confirmation of the original hypothesis4, 72. For instance, different studies have found evidence of genetic moderation only in the female subset of their sample, only in the subset of their sample that was evaluated through an in-depth clinical interview or only when the analysis was restricted to chronic stressors10, 73, 74. As we discuss above, some of the variation in results with different population sub-samples or depression and stress measures may represent true and important heterogeneity in the 5-HTTLPR moderation effect. However another possible explanation for the variation in results within the same study is that some of these secondary findings are actually false positive results that resulted from uncorrected multiple testing. To guard against false positive from the primary studies causing a false positive in our meta-analysis, we did not rely
