Effects of Prevention Messages for Electronic Gambling Machines on Behaviors and Cognitions: Protocol for a Two-Arm Stratified Block: Randomized Controlled Study.

Background: Electronic gambling machines and online gambling are the reputedly most damaging gambling type from a public health perspective. Pop-up messages are often used as a responsible gambling (RG) measure to prevent harm for these screen-based types of gambling. Despite some evidence of effectiveness in the literature for these messages, limitations persist, among which low ecological validity is of particular concern. Objective: This study aims to test (1) the potential of pop-up messages as a prevention measure in a gambling setting and (2) whether this potential is moderated by characteristics of people exposed to the messages. Secondary objectives also tackle some fundamental assumptions of gambling studies conducted in a laboratory setting. Methods: This is a 2-arm stratified block randomized controlled study. In total, 80 participants are recruited under the false pretense of evaluating the realism of a gambling session in a laboratory replicating a bar. Duplicity is also used to make participants believe that they are risking their own money during the experimentation (ie, winnings and losses are real). Participants are randomized to one of the two arms in a 1:1 ratio: (1) experimental group (regular gambling session with prevention pop-up messages presented on a fixed schedule) and (2) active control group (regular gambling session). Outcomes measures include behaviors and cognitive and emotional responses to the pop-up messages. The believability of the gambling session's realism is also evaluated. Results: Recruitment began in February 2024 and concluded in December 2024. Results are expected to be published in 2026. No results are currently available. Conclusions: This study will provide new insights on the efficacy of pop-up messages as a prevention measure for gambling as well as the appropriateness of laboratory studies as a substitute to a real-life setting.