Problem gamblers (PG) are often treated as a uniform group, though they vary in severity—moderate-risk (MR) and high-risk (HR)—as classified by the Canadian Problem Gambling Index (CPGI). This study investigated whether brain responses during uncertain decision-making differ by gambling severity. We hypothesized that the HR group would show distinct neural activity during outcome processing. A homogeneous sample of online poker players with PG was recruited and divided into MR (n = 15) and HR (n = 14) groups. Participants performed the Iowa Gambling Task while undergoing high-density EEG recording. Neural responses to outcomes were analyzed across three time windows (TW3, TW4, TW5). Both groups showed greater neural activity for losses than gains in TW3 and TW5. However, TW4 (220–290 ms post-outcome) revealed a brain map specific to loss processing in the HR group. This suggests greater neural sensitivity to negative outcomes in more severe cases of PG. These results indicate that PG is not a homogeneous disorder; HR individuals display heightened brain reactivity to losses, which may represent increased vulnerability and a potential biomarker for the progression toward gambling disorder.
Giustiniani et al. (Sun,) studied this question.