Cerebellum and obsessive-compulsive disorder: A narrative review of neuroimaging evidence from MRI studies.

Obsessive-Compulsive Disorder (OCD) is a psychiatric condition characterized by recurrent obsessions (intrusive thoughts) and compulsions (repetitive behaviors), with its neurobiological mechanisms remaining a central focus of research. Since the 1980s, neuroimaging studies have revealed significant structural and functional brain differences between OCD patients and healthy controls. Early research primarily relied on the cortico-striato-thalamo-cortical (CSTC) circuit model to explain OCD pathophysiology. However, magnetic resonance imaging (MRI) studies over the past two decades have identified substantial cerebellar abnormalities closely associated with OCD pathogenesis. This review synthesizes evidence from structural MRI (sMRI), diffusion tensor imaging (DTI), functional MRI (fMRI), and meta-analyses to elucidate the cerebellum's role in OCD. Current findings demonstrate that cerebellar abnormalities in OCD patients not only exist independently but also interact with the basal ganglia and CSTC circuits, thereby refining the traditional CSTC model. These findings point to the cerebellum as a potentially critical node in the broader network underlying OCD symptoms. Future directions include exploration of cerebellar-cortical interactions, particularly at the level of symptom-dimensions and subregional specificity, as well as the development of cerebellum-targeted interventions guided by advanced neuroimaging and computational techniques.