Weeland et al.¹ discuss the relationship between subregional thalamic volumes and obsessive-compulsive symptoms (OCS) in children from the general population. The thalamus is the last relay node of the so-called corticostriatal-thalamocortical (CSTC) circuits before information reenters the cortex. There are different CSTC circuits involved in motor, cognitive, and affective/motivational processes whose information is conveyed in parallel through different thalamic nuclei.² Studies have shown that patients with obsessive-compulsive disorder (OCD) show pervasive alterations in these circuits.³ Indeed, such alterations are central to prevailing neurobiological models of OCD, which are largely based on the results from neuroimaging research conducted with clinical OCD samples over the last 3 decades.³ This research includes magnetic resonance imaging studies identifying a range of structural changes in relay nodes within CSTC circuits. In one of the earliest reports, Gilbert et al.⁴ identified enlarged thalamic volumes in a small sample of treatment-naïve children with OCD, which normalized after treatment with paroxetine. Although treatment effects have not been replicated, recent research with larger datasets from the ENIGMA international consortium confirmed these initial findings in unmedicated children with OCD.⁵ Likewise, in a previous study conducted with children from the population-based birth cohort Generation R, the same sample used in the study by Weeland et al.,¹ total thalamic volume was also associated with OCS.⁶