The high heritability of OCD — up to 65% of identical twins share the disease, and 10-25% of children and adolescents with OCD have at least one parent with OCD — points to an important role for genetics in controlling the development and expression of OCD. However, two genome-wide association studies (GWAS) and more defined linkage studies have so far failed to identify replicable genetic loci that confer risk for the development of OCD. This suggests that although OCD exhibits strong evidence of heritability, its inheritance may be mediated, at least in part, by mechanisms extraneous to the actual coding sequence of DNA.
This study will examine whether differences in DNAm exist between OCD-affected and control youth. It will also attempt to discern whether dynamic changes in DNAm occur alongside response to CBT treatment in OCD-affected youth.
Clinical measures and sociodemographic data pertaining to the study Clinical Outcomes following group-based Family Cognitive-Behaviour Therapy in Pediatric Obsessive-Compulsive Disorder (OCD) is obtained from OCD-affected participants who have consented to data-sharing within Canada. All samples (OCD-affected youth and healthy controls) will be collected by BC Children's Biobank staff using buccal swabs. All patient genetic material and data needed to complete this study will be in the Biobank repository.
OCD-affected participants have participated in 12 sessions of group CBT therapy. This CBT group, which is co-facilitated by the OCD clinic psychologist and doctoral-level psychology trainees, includes psychoeducation, exposure and response prevention (E/RP) tasks, challenging cognitive distortions, and anxiety-management strategies. Parents participate in concurrent one-hour parent support groups during the treatment period.
It is anticipated that findings from this study will help to advance psychiatric research generally and knowledge of OCD, its epigenetic underpinnings and its response to CBT in particular.