Limitations of this meta analysis should also be considered in interpreting our findings. First, recoding of the data from some of the studies to use the same analytic framework used by Caspi et al10 may have led to findings that differed from those originally reported.18,26 Second, we could only use individual-level data from 10 of the 14 studies that met inclusion criteria for this meta analysis. However, omission of the other 4 studies would not have biased our conclusions because the 1418 participants in these studies represented only about 10% of the 14 250 total participants included in the meta analysis. Moreover, evaluation of the studies that were published subsequent to 2008 (the cutoff for our analysis of original individual level data) revealed only 1 replication,33 4 nonreplications,31,34,36,39 4 studies with findings in the opposite direction from the original report (eg, L rather than S allele was related to susceptibility),32,37,41,52 and 1 that reported an interaction only after post hoc exclusion of 13% of the participants who were taking psychotropic medications.38 Therefore, review of the aggregate evidence from these studies does not support replication and suggests that the findings of the meta-analysis presented herein were not biased by their noninclusion.
