Previous findings of SUD studies have been somewhat inconsistent but an association between abnormal gamma activities and the abuse of stimulants has been consistently reported. EEG studies show that individuals who use cocaine exhibit decreased gamma band reactivity, which treatments aim to enhance51, and that tobacco use increases gamma activity52, 53. However, it remains unclear whether heightened gamma coherence in IGD patients is common in patients with other behavioral addictions, such as GD. Future comparison studies that include patients with IGD and those with other behavioral addictions will help solve this issue. Although the findings of the present study are somewhat limited in that gamma coherence was not correlated with the IAT scores in the IGD group, there was a positive correlation of gamma coherence with the IAT scores in all groups; this may have been due to a ceiling effect of the IAT scores regarding IGD. Thus, to determine whether gamma coherence could be considered as an endophenotype for IGD, future EEG studies investigating the genotypes of IGD patients on a large scale will be necessary.
