BACKGROUND: Attention deficit/hyperactivity disorder (ADHD) is associated with an increased risk of addiction. However, few studies have compared multiple addiction domains within the same analytic framework using harmonized metrics. This study examined the predictors of addiction severity across alcohol, tobacco, cannabis, internet gaming, and gambling in adults with ADHD symptoms.

METHODS: Adults reporting ADHD symptoms completed an online survey. Z-standardized severity scores were analyzed via linear mixed-effects models (N = 847 observations from 394 participants) alongside demographics, stress (PSS-10), and ADHD symptoms. An exploratory logistic regression (N = 82) predicted gambling problems.

RESULTS: Mixed-effects models revealed no significant main effect of addiction type (all p > .650), indicating that relative severity was comparable across domains. Perceived stress was a significant positive predictor of severity. Current and retrospective ADHD symptoms were not significantly associated with addiction severity. Binary logistic regression identified internet gaming severity as a significant risk factor for the presence of gambling problems (OR = 1.09, p = .037). Alcohol use was not a significant predictor.

CONCLUSIONS: Internet gaming severity was associated with the presence of gambling problems. However, general addiction severity appears to be driven more by perceived stress than by ADHD symptoms themselves. Furthermore, internet gaming may represent a risk factor for gambling problems, though this preliminary finding requires replication.