Brain Morphology Associated With Obsessive-Compulsive Symptoms In 2,551 Children From the General Population.

Abstract Objective Obsessive-compulsive symptoms (OCS) are common in the general population, but it is unclear whether subclinical OCS symptoms and obsessive-compulsive disorder (OCD) are part of a neuroanatomical continuum. The goal of this study was to investigate the relationship between OCS and subcortical and cortical morphology in a population-based sample of children. Method The study included 2551 participants, aged 9-12 years, from the population-based Generation R study. OCS were measured using the Short Obsessive-Compulsive Disorder Screener (SOCS, 7-items caregiver-rated). Structural (3T) MRI scans were processed using FreeSurfer to study the thalamus and other subcortical volumes, intracranial volume, vertex-wise cortical thickness and surface area. We used linear regression models to investigate the association between OCS and brain morphology. Emulating case-control studies from the literature, we compared children scoring above the clinical cut-off of the SOCS (‘probable OCD’ cases, n = 164) with matched children without symptoms. Results Children with probable OCD had larger thalami compared to the control group (Cohen’s d 0.16, p = 0.044). Vertex-wise analysis showed a positive association between OCS and thickness of the right inferior parietal cortex, which disappeared after adjusting for total behavioral problems. SOCS scores correlated negatively with intracranial volume (B = -2444, p = 0.038). Conclusion Children with probable OCD showed thalamus alterations similar to those previously reported in unmedicated children with OCD. OCS showed a stronger association with total intracranial volume than regional brain measures. Longitudinal studies are needed to further elucidate similarities and distinctions between neural correlates of subclinical and clinical OCS.