Differential neural reward processes in internet addiction: A systematic review of brain imaging research

Objectives: This systematic review aims to examine the neural correlates of reward processing in various forms of Internet Addiction (IA) among adults, including generalized IA and specific conditions such as Internet Gaming Disorder (IGD). The study seeks to identify distinct patterns of altered connectivity and activation in reward-related brain regions across different IA subtypes. Methods: We analyzed findings from 44 neuroimaging studies, aligning with the Research Domain Criteria (RDoC) framework. The review focused on three key aspects of reward processing: responsiveness, learning, and valuation. Studies included both structural and functional neuroimaging data from adult populations with various forms of IA. Results: Findings suggest distinct patterns of altered connectivity and activation in reward-related brain regions across different IA subtypes. IGD is associated with widespread abnormalities in both structural and functional connectivity within the reward network, whereas excess social media use primarily affects the amygdala-striatal system. However, methodological limitations, including variability in IA definitions, lack of comparative studies between IA subtypes, and predominance of cross-sectional designs, hinder definitive conclusions. Conclusion: This review underscores the need for a nuanced approach to IA, recognizing potentially distinct neural mechanisms across subtypes. Such insights could inform the development of targeted interventions and enhance the clinical utility of IA research and treatment. Future research should address current methodological limitations to provide more definitive conclusions about the neurobiological underpinnings of various forms of IA.