This study evaluated the magnitude of the association between allelic variation at 5HTTLPR and alcohol dependence in 22 case-control studies. Findings indicated a significant but modest association, characterized by a 15% greater likelihood of the presence of at least 1 s allele among individuals with alcohol dependence relative to control participants. This finding provides an estimate of the strength of results from a prior meta-analysis (Feinn et al., 2005) and extends these results to include 7 additional studies. However, evaluation of publication bias indicated that only 9 unpublished studies with null results would be necessary to reduce the magnitude of this result to non-significance. Visual inspection of the funnel plot did not indicate bias; however, a significant moderating effect of year of publication and study sample size suggest that publication bias may be an issue relative to this association. Thus, despite the presence of a significant effect across 22 studies, these results should be interpreted with caution.
