The Longitudinal Relationship Between Brain Morphology and Obsessive-Compulsive Symptoms in Children From the General Population

OBJECTIVE: Cross-sectional studies in children with obsessive-compulsive disorder (OCD) have found larger thalamic volume, which is not found at later ages. We previously found that 9- to 12-year-old children from the general population with clinical-level obsessive-compulsive symptoms (OCS) also have a larger thalamus. Thus, using a longitudinal design, we studied the relationship among thalamic volume, cortical maturation, and the course of OCS.

METHOD: Children from the population-based Generation R Study underwent 1 or 2 (N = 2,552) magnetic resonance imaging (MRI) scans between the age of 9 and 16 years (baseline 9-12 years, follow-up 13-16 years). OCS were assessed with the Short Obsessive-Compulsive Disorder Screener (SOCS) questionnaire using both continuous and clinical cut-off measures to identify children with "probable OCD." We applied linear regression models to investigate the cross-sectional relationship between brain morphology and OCS at age 13 to 16 years. Linear mixed-effect models were fitted to model the bidirectional longitudinal relationship between thalamus and OCS and the thalamus and cortical morphology.

RESULTS: Thalamic volume was not different between probable OCD cases and controls at age 13 to 16 years. Higher baseline thalamic volume predicted a relative persistence of OCS and a flatter slope of thinning in 12 cortical regions.

CONCLUSION: Larger thalamic volume may be a subtle biomarker for persistent OCS symptoms. The persistence of OCS and cortical thickness in relation to earlier larger thalamic volume may reflect being at an earlier stage in neurodevelopment. Longitudinal designs with repeated multimodal brain imaging are warranted to improve our understanding of the neurodevelopmental processes underlying OCS and OCD.

STUDY PREREGISTRATION INFORMATION: Relationship between obsessive-compulsive symptoms and brain morphology in school-aged children in the general population; https://osf.io/; y6vs2.