PET imaging reveals brain functional changes in internet gaming disorder

Background Internet gaming disorder is an increasing problem worldwide, resulting in critical academic, social, and occupational impairment. However, the neurobiological mechanism of internet gaming disorder remains unknown. The aim of this study is to assess brain dopamine D-2 (D-2)/Serotonin 2A (5-HT2A) receptor function and glucose metabolism in the same subjects by positron emission tomography (PET) imaging approach, and investigate whether the correlation exists between D-2 receptor and glucose metabolism. Methods Twelve drug-naive adult males who met criteria for internet gaming disorder and 14 matched controls were studied with PET and C-11-N-methylspiperone (C-11-NMSP) to assess the availability of D-2/5-HT2A receptors and with F-18-fluoro-D-glucose (F-18-FDG) to assess regional brain glucose metabolism, a marker of brain function. C-11-NMSP and F-18-FDG PET imaging data were acquired in the same individuals under both resting and internet gaming task states. Results In internet gaming disorder subjects, a significant decrease in glucose metabolism was observed in the prefrontal, temporal, and limbic systems. Dysregulation of D-2 receptors was observed in the striatum, and was correlated to years of overuse. A low level of D-2 receptors in the striatum was significantly associated with decreased glucose metabolism in the orbitofrontal cortex. Conclusions For the first time, we report the evidence that D-2 receptor level is significantly associated with glucose metabolism in the same individuals with internet gaming disorder, which indicates that D-2/5-HT2A receptor-mediated dysregulation of the orbitofrontal cortex could underlie a mechanism for loss of control and compulsive behavior in internet gaming disorder subjects.