Objective: Internet gaming disorder (IGD) is a growing problem, particularly among adolescents. Although cocaine- and amphetamine- regulated transcript (CART) has been explored as a potential biomarker for addictive disorders, its relationship with IGD remains poorly understood. This study investigated the differences in serum CART levels between adolescents with IGD and healthy controls (HCs) in order to find potential biomarkers as a therapeutic target in IGD. Additionally, we investigated correlations of serum CART levels with personality traits within the IGD group. Methods: A total of 114 adolescents participated in this study (43 in the IGD group and 71 in the HC group). Blood samples (10 mL) were collected and serum CART concentrations were determined using an enzyme-linked immunosorbent assay. Participants also completed the Junior Temperament and Character Inventory. Results: Serum CART levels in the IGD group were significantly lower than those in the HC group (p<0.05). IGD participants had higher novelty-seeking and harm-avoidance traits, accompanied by reduced persistence, self-directedness, and cooperativeness. Notably, a significant correlation emerged between serum CART levels and cooperativeness within the IGD group. Lower cooperativeness trait scores could indicate reduced social interaction. Conclusion The present findings suggest serum CART levels might serve as a neurobiological marker for cooperativeness function in adolescents with IGD.

Objective: Vulnerability to internet gaming disorder (IGD) has increased as internet gaming continues to grow. Cocaine- and amphetamine-regulated transcript (CART) is a hormone that plays a role in reward, anxiety, and stress. The purpose of this study was to identify the role of CART in the pathophysiology of IGD. Methods: The serum CART levels were measured by enzyme-linked immunosorbent assay, and the associations of the serum CART level with psychological variables were analyzed in patients with IGD (n=31) and healthy controls (HC) (n=42). Results: The serum CART level was significantly lower in the IGD than HC group. The IGD group scored significantly higher than the HC group on the psychological domains of depression, anxiety, the reward response in the Behavioral Activation System and Behavioral Inhibition System. There were no significant correlations between serum CART level and other psychological variables in the IGD group. Conclusion Our results indicate that a decrease in the expression of the serum CART level is associated with the vulnerability of developing IGD. This study supports the possibility that CART is a biomarker in the pathophysiology of IGD.