Thalamic Subregions and Obsessive-Compulsive Symptoms in 2,500 Children From the General Population

OBJECTIVE: Pediatric obsessive-compulsive disorder (OCD) and clinically relevant obsessive-compulsive symptoms (OCS) in the general population are associated with increased thalamic volume. It is unknown whether this enlargement is explained by specific thalamic subregions. We investigated the relationship between OCS and volume of thalamic subregions in a population-based sample of children. METHOD: OCS were measured in children (9-12 years) from the Generation R Study using the Short Obsessive-Compulsive Disorder Screener (SOCS). Thalamic nuclei volumes were extracted from structural 3T MRI scans using the ThalamicNuclei pipeline and regrouped into anterior, ventral, intralaminar/medial, lateral and pulvinar subregions. Volumes were compared between children with symptoms above clinical cut-off ('probable OCD' cases, SOCS >= 6, n = 156) and matched children without symptoms (n = 156). We fitted linear regression models to investigate the association between continuous SOCS score and subregional volume in the whole sample (N = 2500). RESULTS: Children with probable OCD had larger ventral nuclei compared with children without symptoms (d = 0.25, p = 0.025, pFDR = 0.126). SOCS score showed a negative association with pulvinar volume when accounting for overall thalamic volume (β = -0.057, p = 0.009, pFDR = 0.09). However, these associations did not survive multiple testing correction. CONCLUSION: Our results suggest that individual nuclei groups contribute in varying degrees to overall thalamic volume in children with probable OCD, although this did not survive multiple comparisons correction. Understanding the role of thalamic nuclei and their associated circuits in pediatric OCD could lead towards treatment strategies targeting these circuits