In main effect analyses (Table 3), there was no significant evidence of association between high methylation level at SLC6A3 CpG site cg13202751 and lifetime PTSD after adjusting for age, sex, socio-economic position, race, smoking, number of traumatic events, PBMC counts, and lifetime depression (p = 0.39). This evidence concerns the gene SLC6A3 and depressive symptom measurement.