Objective: Internet gaming disorder (IGD) shares core clinical features with other addictive disorders, such as gambling disorder and substance use disorder. Designation of IGD as a formal disorder requires elucidation of its neurobiological features and comparison of these with those of other addictive disorders. The aims of the present study were to identify the neurobiological features of the resting-state brain of patients with IGD, alcohol use disorder (AUD), and healthy controls, and to examine brain regions related to the clinical characteristics of IGD.

Method: Functional magnetic resonance imaging was performed on 16 subjects with IGD, 14 subjects with AUD, and 15 healthy controls during the resting-state. We computed regional homogeneity (ReHo) measures to identify intrinsic local connectivity and to explore associations with clinical status and impulsivity.

Results: We found significantly increased ReHo in the posterior cingulate cortex (PCC) of the IGD and AUD groups, and decreased ReHo in the right superior temporal gyrus (STG) of those with IGD, compared with the AUD and HC groups. We also found decreased ReHo in the anterior cingulate cortex of patients with AUD. Scores on Internet addiction severity were positively correlated with ReHo in the medial frontal cortex, precuneus/PCC, and left inferior temporal cortex (ITC) among those with IGD. Furthermore, impulsivity scores were negatively correlated with that in the left ITC in individuals with IGD.

Conclusion: Our results provide evidence of distinctive functional changes in the resting-state of patients with IGD and demonstrate that increased ReHo in the PCC may be a common neurobiological feature of IGD and AUD and that reduced ReHo in the STG may be a candidate neurobiological marker for IGD, differentiating individuals with this disorder from those with AUD and healthy controls.