Prof. T. Simon Memorial National Seminar, 2024 ISBN: 978-81-964183-9-7 262 Neuropsychological Perspective on Brain Function in Substance Use Disorder *Haneena Sulthana K. P., ** Sandhya Aravind C.A. *Research Scholar, **Assistant Professor, Department of Psychology, Sree Sankaracharya University of Sanskrit, Kalady. Abstract Substance Use Disorders (SUDs) are chronic conditions characterized by compulsive drug use despite adverse consequences, driven by complex neurobiological and psychological mechanisms. Neurocognitive impairments are a critical aspect of SUDs, with deficits in domains such as impulse control, attention, decision-making, and emotional regulation. This systematic review aims to compile current evidence on the neurocognitive deficits associated with SUDs and their underlying neural mechanisms, particularly focusing on the prefrontal cortex, insula, and striatal pathways. Research indicates that chronic substance use leads to alterations in brain regions critical for executive functions and decision-making, contributing to maladaptive behaviours and treatment challenges. Neuroimaging studies reveal significant disruptions in resting-state functional connectivity and neuroadaptive changes in brain reward circuits, which are linked to increased vulnerability, cognitive impairments, and relapse risk in individuals with SUDs. Moreover, the interaction of co-occurring mental illnesses and cognitive impairments complicates the neurobiological terrain of addiction, emphasizing the necessity of integrated treatment modalities. In order to lessen these impairments and promote treatment outcomes, this review also discusses prospective therapeutic approaches such as cognitive-behavioural therapy (CBT) and cognitive enhancement therapies. It is crucial to comprehend the neurobiological and neurocognitive aspects of SUDs in order to create more focused and successful addiction therapies. Keywords; Substance use disorder, neurocognitive impairment, brain functions, brain regions Substance Use Disorders (SUDs) are intricate, long-lasting diseases marked by compulsive substance use and seeking in spite of grave consequences. Changes in brain function and structure, particularly in regions linked to reward processing, executive control, and emotional regulation, constitute the neurobiological basis of SUDs. Treatment for SUDs is extremely difficult since a mix of genetic, environmental, and psychosocial factors frequently contribute to these changes. One of the main characteristics of SUDs is neurocognitive impairments, which include deficiencies in impulse control, attention, memory, and decision-making. These impairments lead to the persistence of addictive behaviours and high relapse rates.