Unraveling the Neurobiological Underpinnings of OCD

Аннотация

Obsessive–Compulsive Disorder (OCD) is a SUBMITED 22 January 2025 heterogeneous psychiatric condition marked by ACCEPTED 29 February 2025 intrusive obsessions and ritualistic compulsions that PUBLISHED 25 March 2025 VOLUME Vol.07 Issue03 2025 significantly impair functioning and quality of life. Advances in neuroimaging have substantially clarified CITATION its complex neurobiological basis. Structural findings frequently demonstrate morphological alterations in the orbitofrontal cortex, anterior cingulate cortex, and COPYRIGHT striatum, linked to both gray and white matter © 2025 Original content from this work may be used under the terms disruptions. Functional neuroimaging studies highlight of the creative commons attributes 4.0 License. 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. Keywords: Obsessive–Compulsive Disorder (OCD); Cortico-Striato-Thalamo-Cortical Loop; Neuroimaging; Structural and Functional Alterations; Connectome; Biomarkers; Personalized Medicine. The American Journal of Medical Sciences and Pharmaceutical Research 165 https://www.theamericanjournals.com/index.php/tajmspr The American Journal of Medical Sciences and Pharmaceutical Research INTRODUCTION: Neurobiological inquiries into OCD can be traced back to the 1980s, when pioneering studies utilized positron Obsessive–Compulsive Disorder (OCD) is characterized emission tomography (PET) to detect metabolic by intrusive, recurrent thoughts (obsessions) and hyperactivity in frontal-striatal circuits [6, 8]. These repetitive, ritualized behaviors or mental acts foundational investigations helped establish the now- (compulsions), which individuals feel compelled to classic model involving cortico-striato-thalamo-cortical perform in order to reduce anxiety or distress. These (CSTC) circuits as a framework for understanding OCD’s symptoms can substantially interfere with daily neurobiological underpinnings [4, 6]. Over subsequent functioning, strain interpersonal relationships, and decades, research expanded to encompass various negatively impact overall quality of life [1, 2]. neuroimaging modalities. Magnetic Resonance Imaging Epidemiological studies estimate a lifetime prevalence (MRI) enabled detailed structural analyses, highlighting of OCD ranging from 1% to 3%, making it one of the gray and white matter abnormalities in cortical and more common psychiatric disorders worldwide [2, 3]. subcortical regions [9, 10]. Functional MRI (fMRI), Given its prevalence and the profound burden it particularly in resting-state paradigms, shed light on imposes, OCD has become an important subject for atypical connectivity patterns, while PET and Single translational research aimed at refining diagnostic Photon Emission Computed Tomography (SPECT) procedures and improving therapeutic outcomes [4]. continued to reveal valuable data on cerebral The clinical presentation of OCD involves obsessions— metabolism and neurotransmitter function [11, 12]. unwanted, persistent thoughts, impulses, or images More recent methods such as diffusion tensor imaging that generate significant anxiety—and compulsions— (DTI) and magnetic resonance spectroscopy (MRS) have ritualized behaviors or mental routines performed to further enriched understanding of white matter alleviate the distress produced by obsessions. Common integrity and metabolic deviations in brain networks obsessional themes include contamination fears, pivotal to obsessive–compulsive symptoms [4, 13]. aggressive or sexual thoughts, a need for symmetry, These technological strides, supported by improved and excessive doubts about safety. Corresponding computational and analytic techniques, underscore compulsions often manifest in repetitive washing, that multiple neurocircuits beyond the fronto-striatal checking, counting, ordering, or seeking reassurance. loop co