Abstract
Objective Obsessive-compulsive symptoms (OCS) in the population have been linked to obsessive-compulsive disorder (OCD) in genetic and epidemiological studies. Insulin signaling has been implicated in OCD. We extend previous work by assessing genetic overlap between OCD, population-based OCS, and central nervous system (CNS) and peripheral insulin signaling.
Methods We conducted genome-wide association studies (GWASs) in the population-based Philadelphia Neurodevelopmental Cohort (PNC, 650 children and adolescents) of the total OCS score and six OCS factors from an exploratory factor analysis of 22 questions. Subsequently, we performed polygenic risk score (PRS) analysis to assess shared genetic etiologies between clinical OCD (using GWAS data from the Psychiatric Genomics Consortium), the total OCS score and OCS factors. We then performed gene-set analyses with a set of OCD-linked genes centered around CNS insulin-regulated synaptic function and PRS analyses for five peripheral insulin signaling-related traits. For validation purposes, we explored data from the independent Spit for Science population cohort (5047 children and adolescents).
Results In the PNC, we found a shared genetic etiology between OCD and ‘impairment’, ‘contamination/cleaning’ and ‘guilty taboo thoughts’. In the Spit for Science cohort, we were able to validate the finding for ‘contamination/cleaning’, and additionally observed genetic sharing between OCD and ‘symmetry/counting/ordering’. The CNS insulin-linked gene-set associated with ‘symmetry/counting/ordering’. We also identified genetic sharing between peripheral insulin signaling-related traits (type 2 diabetes and the blood levels of HbA1C, fasting insulin and 2 hour glucose) and OCD as well as certain OCS.
Conclusions OCD, OCS in the population and insulin-related traits share genetic risk factors, indicating a common etiological mechanism underlying somatic and psychiatric disorders.
Footnotes
Disclosures: Authors JB, JW, WD, DY, CM, JC, RS, PA, ML and CB have no conflicts of interest. JMS has received honoraria from Abide Therapeutics regarding treatments for OCD and related disorders. In the past 3 years, JKB has been a consultant to / member of advisory board of / and/or speaker for Shire, Roche, Medice, and Servier. He is not an employee of any of these companies, and not a stock shareholder of any of these companies. He has no other financial or material support, including expert testimony, patents, royalties. BF has received educational speaking fees from Medice and Shire. GP is director of Drug Target ID (DTID) Ltd.