Fig. 2

Meta-analysis of the 5-HTTLPR and major depressive disorder according to DSM IV among 17 Caucasian populations. The center of a box and the horizontal line (logarithm) indicate the odds ratio (OR) and the 95% confidence interval (CI) in each study, with the areas of the boxes representing the weight of each study. The summary OR based on the random effects model is represented by the middle of a diamond whose width indicates the 95% CI. The summary OR is shown by the dotted vertical line. Statistical heterogeneity between studies was assessed with Cochran’s Q test (Q = 12.1, p = 0.74). Summary OR = 1.31 (95% CI = 1.14–1.52). SS + LS versus LL