Background: Post-traumatic stress disorder (PTSD) results from trauma, but not all individuals develop PTSD after trauma. Differences in susceptibility to PTSD may be related to epigenetic differences between cases and trauma-exposed controls that can provide insight into the biological processes underlying the disorder. The Psychiatric Genomics Consortium (PGC) PTSD Epigenetics Workgroup has the goal to identify DNA methylation-based epigenetic biomarkers that serve as important indicators of PTSD, to characterize which of these biomarkers identify individuals at increased risk following trauma, and how these biomarkers might vary by sex and trauma type.
Method: Ten cohorts, military and civilian, contributed blood-derived DNA methylation data (HumanMethylation450 BeadChip) from 1,896 PTSD cases (42%) and trauma-exposed controls (58%). Each CpG site was tested for association with current PTSD using linear models that control for age, genomic-derived ancestry estimates, leukocyte cell proportions and study-specific covariates followed by meta-analysis using inverse normal p-value combination and false discovery rate (FDR) estimation. Civilian and sex-stratified meta-analyses were also conducted.
Results: We identified ten CpG sites associated with PTSD (9.61E-07
Conclusions: These meta-analyses have identified associations between CpG sites in multiple biologically relevant genes and PTSD. Results suggest that groups with different trauma exposures and biological backgrounds may have distinct epigenetic patterns that may be targeted for intervention.