Effectiveness of Internet-Based Personalized Normative Feedback Among Individuals Experiencing Problem Gambling: Randomized Controlled Trial.

This study aimed to examine whether fully automated and Internet-based personalized normative feedback (GAMCHECK) improves problem gambling symptoms and behaviors. We used a randomized parallel-group superiority design to examine whether GAMCHECK would be more effective than an assessment-only (AO) condition at 12-week follow-up. This study was conducted online using questionnaires and the LINE app. Participants were recruited through online surveys. All outcomes were assessed using Internet-based questionnaires. We used a linear mixed model to assess the effects of GAMCHECK on scores for the Gambling Symptom Assessment Scale (GSAS) as the primary outcome; secondary outcomes were the Gambling Related Cognitions Scale (GRCS), Patient Global Impression of Change (PGI-C), number of gambling days, money spent on gambling, and help-seeking behaviors. With data from 274 participants (GAMCHECK: n = 141; AO: n = 133), we demonstrated that GAMCHECK was more effective solely on GRCS than AO at both one-week and four-week follow-up. Furthermore, by the 12-week follow-up, GAMCHECK significantly more effective than AO on gambling symptoms measured by the GSAS, number of gambling days and amount of money spent on gambling during the prior week, GRCS, and PGI-C at 12-week follow-up. No significant effects were found for help-seeking behaviors. Cognitive distortion mediated the effect on change in GSAS scores. GAMCHECK was significantly effective in improving gambling symptoms, number of gambling days, amount of money spent on gambling, and cognitive distortion. However, regarding help-seeking behavior, further refinement of GAMCHECK is necessary to motivate problem gamblers to take actions to solve their problems.