The role of the cerebellum in internet gaming disorder-A systematic review.

Recent studies increasingly highlight involvement of the cerebellum in drug craving and addiction. However, its exact role, that is, whether the cerebellum is a critical component of a brain network underlying addictive behaviour, or whether it rather is a facilitator or mediator, is still unclear. Findings concerning the newly recognized internet gaming disorder (IGD) suggest that changes in cerebellar connectivity and functioning are associated with behavioural/non-substance addiction. Here, we systematically review the literature on IGD and cerebellar involvement following the PRISMA guidelines. A total of 13 neuroimaging studies met the inclusion criteria. Studies utilized a broad range of diagnostic instruments and resulting cut-off criteria, rendering it difficult to compare findings. Results on altered cerebro-cerebellar connectivity in patients with IGD are mixed; most studies report altered or increased functional connectivity. Moreover, decreased cerebellar grey matter volume is reported. Studies have further indicated that differential activation patterns in the cerebellum may enable discrimination between healthy subjects and subjects with IGD, even allowing for prediction of treatment outcomes. Given the strong connectivity between the cerebellum and cerebral regions, the cerebellum may act as an intermediary between regions involved in craving and addiction and consequently affect symptoms of IGD. Results suggest differential involvement of the cerebellar lobes, emphasizing a need for high-resolution parcellation of the cerebellum in future studies. However, the studies included in the present review have small sample sizes and include mostly male participants. Thus, results may have limited generalizability yet highlight a crucial role of the cerebellum in IGD that needs further investigation.