Self-directed treatments for gambling disorder have been developed to attract individuals who are reluctant to seek formal treatment. Self-directed treatments provide individuals with information and support to initiate a recovery program without attending formal treatment. In this study, an online version of a previously evaluated telephone-based intervention package is compared to a brief online normative feedback intervention called Check Your Gambling. In a randomized controlled trial design, participants with gambling problems who were not interested in formal treatment (N = 181) were recruited through media announcements. After a baseline telephone assessment, participants were assigned to have access to either the brief Check Your Gambling, or the extended self-management tools intervention. Follow-up assessments were conducted at 3, 6, and 12 months post baseline by blinded interviewers. Participant nominated collaterals were contacted to validate self-reported gambling involvement. The follow-up rate at 12 months was 78%. Participants in both conditions showed significant reductions in days of gambling and problem severity but no differences between conditions were found, contrary to the primary hypothesis. Lack of previous treatment for gambling and higher baseline self-efficacy predicted fewer days of gambling in both conditions. Self-efficacy increased over time but did not appear to mediate changes in gambling. Participants who were most engaged in the extended online program showed better outcomes. Those with low engagement showed a slower trajectory of change but equivalent improvements by 12 months. The extended online intervention was not associated with better outcomes than the brief Check Your Gambling intervention. Future research needs to explore the attractiveness, uptake, and effectiveness of online interventions with and without therapist support to understand their potential role in gambling disorder treatment systems.Trial Registration ISRCTN06220098.
Keywords: Brief intervention; Clinical trial; Gambling disorder; Normative feedback; Online intervention.