No evidence for intervention-associated DNA methylation changes in monocytes of patients with posttraumatic stress disorder or anorexia nervosa

DNA methylation patterns have been shown to be responsive to environmental cues. These observations have sparked interest in the potential for psychological interventions to influence epigenetic processes. A few studies have observed correlations between DNA methylation changes and therapy outcome, however, most did not control for changes in cell composition from pre- to post-therapy. Here, we addressed this limitation and analyzed DNA methylation patterns by targeted bisulfite sequencing of commonly assessed candidate genes in isolated monocytes from 60 female patients with post-traumatic stress disorder (PTSD) before and after in-patient treatment. Furthermore, in two patients with PTSD and three patients with anorexia nervosa (AN), whole-genome bisulfite sequencing (WGBS) was performed before and after intervention, to identify novel genomic regions with large pre-to-post intervention DNA methylation changes. There were only few WGBS-nominated candidate regions associated with therapy outcome, and these could not be validated in the whole cohort. Furthermore, we observed no intervention-associated changes in commonly investigated candidate genes (NR3C1, FKBP5, SLC6A4, OXTR). We conclude that there is no evidence for major, recurrent intervention-associated DNA methylation changes in monocytes of patients with either PTSD or AN.