Developing and Strengthening Cannabis Warnings: Warning Message Testing

The purpose of this activity is to identify promising cannabis warning messages from different themes. Participants will be adults who live in the United States, including both people who use cannabis and those who do not use cannabis. In an online within-subjects experiment, participants will be randomly assigned to view 7 cannabis warning messages from different themes developed as part of previous study activities. After viewing each cannabis warning message, participants will rate the message on awareness, clarity, believability, cognitive elaboration, perceived message effectiveness, and reactance. The survey will take 15-20 minutes.

NCT Number	NCT07699198
Lead Sponsor	University of North Carolina, Chapel Hill Collaborators: National Institute on Drug Abuse (NIDA)
Conditions	Cannabis, Marijuana Use
Enrollment	1,500 participants
Start Date	2026-07-13
Primary Completion	2026-11-30 (estimated)
Study Completion	2026-11-30 (estimated)
Updated on ClinicalTrials.gov	2026-07-13