fit an additive or S-dominant model. Further, we attempted to replicate Caspi et al. [2003] by matching their sample and analyses as best we could but still found no evidence for an interaction. Finally, our data suggest that the reported interaction is no more likely for females alone, younger adults, or shorter intervals between SLE and depression/suicidality, despite the review by Uher and McGuffin [2008] suggesting effects were more likely in such subsamples. As there is no evidence for association in our study sample between depression/suicidality and either 5HTTLPR or 5HTTLPR + rs25531, we cannot make any conclusion about the value of including the rs25531 polymorphism. We recently reported an association between MD and rs6354 located ~15.5 kb from, and in linkage equilibrium (r2 = 0.01) with, 5HTTLPR, although the association in the study sample used here (the SSAGA cohort) was not significant [Wray et al., 2009]. We repeated the G × E analyses presented here for genotypes of rs6354 but found no evidence for an interaction (results not presented).
