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.

Obsessive–Compulsive Disorder (OCD), Cortico-Striato-Thalamo-Cortical Loop, Neuroimaging, Structural and Functional Alterations, Connectome, Biomarkers, Personalized Medicine

Eisen, J. L., Mancebo, M. A., Pinto, A., & Rasmussen, S. A. (2006). Impact of obsessive-compulsive disorder on quality of life. Comprehensive Psychiatry, 47(4), 270–275.

Ruscio, A. M., Stein, D. J., Chiu, W. T., & Kessler, R. C. (2010). The epidemiology of obsessive-compulsive disorder in the National Comorbidity Survey Replication. Molecular Psychiatry, 15(1), 53–63.

Kessler, R. C., Berglund, P., Demler, O., Jin, R., Merikangas, K. R., & Walters, E. E. (2005). Lifetime prevalence and age-of-onset distributions of DSM-IV disorders in the National Comorbidity Survey Replication. Archives of General Psychiatry, 62(6), 593–602.

Hazari, N., Narayanaswamy, J. C., & Venkatasubramanian, G. (2019). Neuroimaging findings in obsessive–compulsive disorder: A narrative review to elucidate neurobiological underpinnings. Indian Journal of Psychiatry, 61(Suppl 1), S9–S29.

Pauls, D. L., Abramovitch, A., Rauch, S. L., & Geller, D. A. (2014). Obsessive-compulsive disorder: An integrative genetic and neurobiological perspective. Nature Reviews Neuroscience, 15(6), 410–424.

Baxter, L. R. Jr., Phelps, M. E., Mazziotta, J. C., Guze, B. H., Schwartz, J. M., & Selin, C. E. (1987). Local cerebral glucose metabolic rates in obsessive-compulsive disorder: A comparison with rates in unipolar depression and in normal controls. Archives of General Psychiatry, 44(3), 211–218.

Rauch, S. L., Shin, L. M., & Wright, C. I. (2003). Neuroimaging studies of amygdala function in anxiety disorders. Annals of the New York Academy of Sciences, 985(1), 389–410.

Swedo, S. E., Schapiro, M. B., Grady, C. L., Cheslow, D. L., Leonard, H. L., Kumar, A., … Rapoport, J. L. (1989). Cerebral glucose metabolism in childhood-onset obsessive-compulsive disorder. Archives of General Psychiatry, 46(6), 518–523.

Menzies, L., Achard, S., Chamberlain, S. R., Fineberg, N., Chen, C. H., Del Campo, N., … Bullmore, E. (2008). Neurocognitive endophenotypes of obsessive-compulsive disorder. Brain, 130(12), 3223–3236.

Rotge, J.-Y., Langbour, N., Guehl, D., Bioulac, B., Jaafari, N., Allard, M., … Burbaud, P. (2010). Gray matter alterations in obsessive-compulsive disorder: An anatomic likelihood estimation meta-analysis. Neuropsychopharmacology, 35(3), 686–691.

Saxena, S., Brody, A. L., Schwartz, J. M., & Baxter, L. R. (1999). Neuroimaging and frontal-subcortical circuitry in obsessive-compulsive disorder. British Journal of Psychiatry, 35(Suppl), 26–37.

Perani, D., Colombo, C., Bressi, S., Bonfanti, A., Grassi, F., Scarone, S., … Fazio, F. (1995). [18F]FDG PET study in obsessive–compulsive disorder. A clinical/metabolic correlation study. Psychiatry Research: Neuroimaging, 58(1), 55–64.

Radua, J., & Mataix-Cols, D. (2009). Voxel-wise meta-analysis of grey matter changes in obsessive-compulsive disorder. British Journal of Psychiatry, 195(5), 393–402.

Norman, L. J., Carlisi, C., Lukito, S., Hart, H., Sato, J. R., Anand, N., … Rubia, K. (2016). Structural and functional brain abnormalities in attention-deficit/hyperactivity disorder and obsessive-compulsive disorder: A comparative meta-analysis. JAMA Psychiatry, 73(8), 815–825.

de Wit, S. J., Alonso, P., Schweren, L., Mataix-Cols, D., Lochner, C., Menchón, J. M., … van den Heuvel, O. A. (2014). Multicenter voxel-based morphometry mega-analysis of structural brain scans in obsessive-compulsive disorder. American Journal of Psychiatry, 171(3), 340–349.

Fouche, J. P., van den Heuvel, O. A., & others. (2017). A large multicenter voxel-based morphometry analysis in obsessive-compulsive disorder. Frontiers in Psychiatry, 8, 1–14.

Boedhoe, P. S., Schmaal, L., Abe, Y., van den Heuvel, O. A., & others. (2018). Cortical abnormalities associated with pediatric and adult obsessive-compulsive disorder: Findings from the ENIGMA Obsessive-Compulsive Disorder Working Group. American Journal of Psychiatry, 175(6), 453–462.

Nakamae, T., Narumoto, J., Sakai, Y., Nishida, S., Yamada, K., Nishimura, T., & Fukui, K. (2011). Diffusion tensor imaging and tract-based spatial statistics in obsessive-compulsive disorder. Journal of Psychiatric Research, 45(5), 687–690.

Fan, Q., Yan, X., Wang, J., Chen, Y., Wang, X., Li, C., … Gu, B. (2012). Abnormalities of white matter microstructure in unmedicated obsessive-compulsive disorder and changes after medication. PLoS ONE, 7(4), e35889.

Gan, J. L., Li, X. L., Zhong, B. L., & others. (2017). White matter alterations in never-treated adult patients with obsessive-compulsive disorder. Progress in Neuro-Psychopharmacology & Biological Psychiatry, 76, 7–12.

Peng, Z. W., Xu, T., He, Q. H., Cai, Z. L., & Shen, J. (2012). White matter abnormalities in patients with obsessive-compulsive disorder: A meta-analysis of diffusion tensor imaging studies. Progress in Neuro-Psychopharmacology & Biological Psychiatry, 39(1), 208–214.

Yoo, S. Y., Jang, J. H., Shin, Y. W., Kim, D. J., Park, H. J., & Moon, W. J. (2007). White matter abnormalities in drug-naïve patients with obsessive-compulsive disorder: A diffusion tensor study before and after citalopram treatment. Acta Psychiatrica Scandinavica, 116(3), 211–219.

Bartha, R., Stein, M. B., Williamson, P. C., Drost, D. J., Neufeld, R. W., & Zagon, R. S. (1998). A short echo proton magnetic resonance spectroscopy study of the left caudate in obsessive-compulsive disorder. Psychiatry Research: Neuroimaging, 83(3), 143–151.

Tükel, R., Gürvit, H., Ertekin, B. A., Oztürk, M., Özyurt, G., & Ertekin, E. (2014). Gray matter abnormalities in patients with treatment-naive obsessive-compulsive disorder. Neuropsychiatric Disease and Treatment, 10, 2005–2012.

Zhu, Y., Fan, Q., Wang, X., & Li, Q. (2015). Altered thalamic glutamate levels in unmedicated patients with obsessive-compulsive disorder. Journal of Affective Disorders, 178, 198–204.

Atmaca, M., Yildirim, H., Ozdemir, H., Kara, B., Ozler, S., & Tezcan, E. (2009). Hippocampus and amygdalar volumes in patients with obsessive-compulsive disorder before and after treatment. Psychiatry Research: Neuroimaging, 174(3), 180–185.

Fan, Q., Wu, X., Yao, L., & others. (2017). Reduced glutamate levels in medial prefrontal cortex associated with symptom severity in unmedicated patients with obsessive-compulsive disorder. Journal of Psychiatry & Neuroscience, 42(2), 87–94.

Harrison, B. J., Pujol, J., Soriano-Mas, C., & others. (2009). Altered corticostriatal functional connectivity in obsessive-compulsive disorder. Archives of General Psychiatry, 66(11), 1189–1200.

Beucke, J. C., Sepulcre, J., Eichele, T., & others. (2013). Default mode network subsystem alterations in obsessive-compulsive disorder. British Journal of Psychiatry, 202(5), 1–8.

van der Straten, A. L., Denys, D., van Wingen, G. A., & others. (2017). Prediction of response to cognitive behavioral therapy in obsessive-compulsive disorder with functional MRI: A cross-validated machine learning analysis. NeuroImage: Clinical, 14, 1–9.

Mataix-Cols, D., Wooderson, S., Lawrence, N., Brammer, M. J., Speckens, A., & Phillips, M. L. (2004). Distinct neural correlates of washing, checking, and hoarding symptom dimensions in obsessive-compulsive disorder. Archives of General Psychiatry, 61(6), 564–576.

Nakao, T., Nakagawa, A., Yoshiura, T., & others. (2005). A functional MRI comparison of patients with obsessive-compulsive disorder and normal controls during a Chinese character Stroop task. Psychiatry Research: Neuroimaging, 139(2), 101–114.

Brody, A. L., Saxena, S., Stoessel, P., & others. (1998). Regional brain metabolic changes in patients with obsessive-compulsive disorder treated with paroxetine. American Journal of Psychiatry, 155(10), 1552–1558.

Herrmann, M. J., Montoya, A. K., Schramm, E., & others. (2022). Advances in near-infrared spectroscopy (NIRS) neurofeedback and potential clinical applications in psychiatry. Clinical Neurophysiology, 133, 123–132.

Kopton, I. M., & Kenning, P. (2014). Near-infrared spectroscopy (NIRS) as a new tool for neuroeconomic research. Frontiers in Human Neuroscience, 8, 1–13.

Koseki, S., Nishimura, Y., Takizawa, R., & others. (2013). Near-infrared spectroscopy in obsessive-compulsive disorder: A pilot study. Progress in Neuro-Psychopharmacology & Biological Psychiatry, 40, 115–120.