Impact of Simple Versus Complex Cannabis Advertising Messages and Warnings on US Young Adults’ Product Perceptions

Background: Despite cannabis’ increased popularity, limited research has assessed effects of advertising messages or warnings, particularly their complexity. This study examined effects of advertising message and warning complexity on young adults’ perceptions. Methods: In 2024, US adults ages 18 to 34 (n = 3581; 40.8% past-month cannabis use) completed an online survey-based experiment using a 2 × 3 factorial design (advertising message: simple vs complex; warning: none vs simple vs complex), then reported perceived addictiveness, harm, cautiousness, appeal, and interest (0 = none – 7 = extremely). Multivariable regression assessed conditions and their interactions with 1 another and past-month use in relation to perception outcomes. Results: Complex (vs simple) advertising message exposure was associated with higher perceived addictiveness ( B = 0.35, standard error [SE] = 0.06), harm ( B = 0.21, SE = 0.06), appeal ( B = 0.34, SE = 0.06), and interest ( B = 0.20, SE = 0.06). Complex (vs no) warning exposure was associated with higher addictiveness ( B = 0.23, SE = 0.08); simple or complex warning exposure was associated with higher harm ( B = 0.20, SE = 0.07; B = 0.20, SE = 0.08). A significant interaction indicated that complex advertising message exposure was associated with larger increases in addictiveness and harm among nonusers but minimal effect in users. In analysis stratified by past-month use, an interaction among users indicated that complex warning exposure was associated with higher addictiveness among those exposed to the simple advertising message but had the opposite effect in those exposed to the complex advertising message. Conclusions: Desired effects were yielded by complex advertising messages (interest, appeal) and warnings (risk). However, complex advertising messages may overpower effects of complex warnings among users. Additional research is needed to understand these dynamics and inform regulations.