Background <p>This study is a randomized controlled trial evaluating an adaptation of the Future Possible Selves Task (FPST). This adaptation focuses on possible hope for and feared future selves related to drinking alcohol. The study will evaluate whether the FPST can reduce the typical increase in self-concept related to drinking (i.e., drinking identity) and accompanying escalation in alcohol misuse that commonly occurs during the transition out of high school in the United States. Its use of a factorial design will also provide a test of the most optimal FPST condition(s) to do so.</p> Method <p>The study will recruit 528 soon-to-graduate or recently-graduated high school students from the states of Texas and Washington. Recruitment will occur in two waves (once per year) at each site. Participants need to report drinking alcohol within the last year and interest in either decreasing or not increasing their drinking. The study has a 2 (write about future hoped-for self vs. not) × 2 (write about a future feared self vs. not) × 2 (dose: write once vs. write once per week for 3&#xa0;weeks) design for the FPST. Procedures will occur online. Participants’ drinking identities, drinking behaviors, and other cognitive/affective/motivational factors related to drinking will be evaluated. Participants will be followed up to 12&#xa0;months post-FPST.</p> Discussion <p>Analyses will evaluate the efficacy of the adapted FPST to prevent the typical escalation of drinking identity and alcohol misuse that commonly accompany the transition out of high school. It is expected that the FPST condition, which includes three doses of writing about a possible hoped-for and feared self, will be most effective in preventing escalation. If successful, the FPST has the potential to be a novel, scalable strategy for the prevention and intervention of alcohol misuse.</p> Trial registration <p>Clinicaltrials.gov registration # NCT06191861, registration date: December 8, 2023.</p>