Statistical analyses were performed with PLINK v1.07 (http://pngu.mgh.harvard.edu/purcell/plink/) to calculate Hardy-Weinberg equilibrium, and build logistic regression models for binary outcome variable (DEP) and linear regression models for continuous outcome variables (BSI-DEP, BSI-ANX). Additive genetic model was applied, sex and age were covariates in all analyses. The two population data were analyzed together to increase the power, especially for GxE interaction tests. For power calculation, see Table A in S1 File. Because the 5-HTTLPRxlife events (RLE or CHA) interaction results were very similar in the first analysis (see Table B in S1 File) all subsequent statistical calculation used life events as grouped variables to make it comparable to the Bayesian analysis. Main effects of 5-HTTLPR and 5-HTTLPRxRLE interaction were separately tested on each outcome variable in the total combined population and separately for subjects who were 30 years of age or below (≤30) and for those who were above 30 (>30). Other statistical analyses were performed with IBM SPSS 21.0 for Windows. We also used R Project [25] to support some of the PLINK analyses. All statistical testing used two-tailed p<0.05
