Unraveling the Neurobiological Underpinnings of OCD

Obsessive–Compulsive Disorder (OCD) is a heterogeneous psychiatric condition marked by intrusive obsessions and ritualistic compulsions that significantly impair functioning and quality of life. Advances in neuroimaging have substantially clarified its complex neurobiological basis. Structural findings frequently demonstrate morphological alterations in the orbitofrontal cortex, anterior cingulate cortex, and striatum, linked to both gray and white matter disruptions. Functional neuroimaging studies highlight hyperactivity within cortico-striato-thalamo-cortical (CSTC) loops and aberrant connectivity involving the parietal cortex, limbic structures, and cerebellum. Task-based paradigms underscore that different symptom dimensions (e.g., contamination fears, checking, hoarding) activate partially distinct yet overlapping cortical–subcortical networks. Integrating these structural and functional perspectives supports a connectome-based framework, in which OCD emerges from dysregulated interactions among diverse brain systems involved in cognitive control, emotional regulation, and habit learning. Emerging biomarkers—such as caudate volume, anterior cingulate metabolites, and orbitofrontal connectivity—show promise for predicting response to pharmacotherapy and cognitive-behavioral therapy. Future investigations may expand on these findings through larger longitudinal cohorts, inclusion of pediatric populations, and implementation of multi-omic approaches that integrate genetic, epigenetic, and neuroimaging data. This synthesis of current evidence underscores the potential for refined diagnostic stratification, personalized therapeutic interventions, and enhanced monitoring of treatment efficacy.