Background <p>Childhood environmental unpredictability (CEU) is recognized as a contributing factor to the maintenance and development of problematic gaming (PG) in adulthood by undermining individuals’ psychological well-being. According to the cognitive vulnerability-stress model, cognitive schemas, such as unpredictability beliefs, may moderate the indirect pathway of CEU on PG via psychological distress. However, direct empirical evidence remains limited.</p> Methods <p>Using cross-sectional design and convenience sampling, a total of 1,255 Chinese college students aged 17 to 28 years (54.50% female, <i>M</i>_age = 21.36, SD = 1.30) completed self-report questionnaires assessing demographic characteristics, CEU, psychological distress, unpredictability beliefs, and PG. A moderated mediation model was conducted to test the hypotheses.</p> Results <p>After controlling for gender, age, and annual family income, findings showed that CEU was positively associated with PG (β = 0.252, SE = 0.029, 95% CI [0.195, 0.307]). Additionally, psychological distress partially mediated the relationship between CEU and PG (β = 0.144, SE = 0.016, 95% CI [0.114, 0.177]). Moreover, unpredictability beliefs moderated the first stage of the mediation pathway. Specifically, higher unpredictability beliefs strengthened the association between CEU and psychological distress (β = 0.114, SE = 0.025, 95% CI [0.094, 0.194]).</p> Conclusions <p>These findings provide further insights into the impact of CEU on individuals’ psychological and behavioral development, offer empirical support for the cognitive vulnerability-stress model, and help identify the potential targets for mitigating psychological distress and PG among college students.</p>