Lower synaptic density and its association with cognitive dysfunction in patients with obsessive-compulsive disorder

BackgroundUnderstanding synaptic alteration in obsessive-compulsive disorder (OCD) is crucial for elucidating its pathological mechanisms, but in vivo research on this topic remains limited.AimsThis study aimed to identify the synaptic density indicators in OCD and explore the relationship between cognitive dysfunction and synaptic density changes in OCD.MethodsThis study enrolled 28 drug-naive adults with OCD aged 18–40 years and 16 healthy controls (HCs). Three-dimensional T1-weighted structural magnetic resonance imaging and 18F-SynVesT-1 positron emission tomography were conducted. Cognitive function was assessed using the Wisconsin Cart Sorting Test (WCST) in patients with OCD and HCs. Correlative analysis was performed to examine the association between synaptic density reduction and cognitive dysfunction.ResultsCompared with HCs, patients with OCD showed reduced synaptic density in regions of the cortico-striato-thalamo-cortical circuit such as the bilateral putamen, left caudate, left parahippocampal gyrus, left insula, left parahippocampal gyrus and left middle occipital lobe (voxel p