Subgroup analyses of study design, type of PTSD assessed and quality characteristics in the Meta-Analysis of <i>5-HTTLPR</i> polymorphisms and Post-traumatic Stress Disorder (PTSD) in the triallelic approach.

‡<p>K: Number of studies; ^#Number of alleles S or L duplicates the number of participants as each participant has two alleles (S, L or one of each one); OR: Odds Ratio; 95% CI: 95% Confident Interval; ^&Chi-squared test for subgroup differences; NA: Not applicable; <b>^†</b>HWE: Hardy-Weinberg Equilibrium.