This discrete choice experiment (DCE) study aims to address gaps in cannabis packaging regulatory research by testing how variations in cannabis packaging and health warning design impact reactions to packaging and intentions about cannabis use. The goal of this work is to identify the most effective combination of health warning features to improve consumer awareness of cannabis health risks. Establishing criteria for cannabis products in the US is critical because inconsistent state guidelines have resulted in contradictory policies in legal retail states, arguably leading to increased hazardous use and failure to meet public health standards. The contributions of this study's outcomes are expected to be significant because they will benefit public health as cannabis becomes available in legal retail markets and regulatory and governmental agencies seek effective ways to communicate cannabis risks to the public.

The DCE will be conducted via a self-administered online questionnaire, with inclusion criteria assessed before assignment to choice set conditions. Participants will be residents of legal-retail cannabis use states, able to legally purchase cannabis (21 or older), who have used cannabis in the past 30 days (i.e., current use). Frequency of cannabis use (i.e., monthly, weekly, daily), mode (e.g., flower, vape, etc.), and dose (i.e., THC level) will be measured through self-report. Inclusion criteria are reported using cannabis (any mode) in the past 30 days. Consented participants will be presented with descriptions of cannabis packaging attributes and an example choice set to become familiar with DCE tasks. Participants will be asked to imagine the cannabis products in the DCE as the only choices they have available to them "in the near future" and to evaluate images within this scenario. Participants will be randomly assigned to view 16 choice sets. To optimize the evaluation of preferences and reduce respondent burden, we will assign contrasting labels to "choice sets," each of which will include 4 images of products in such a way that each attribute level appears an equal number of times in combination with all other attribute levels. Presentation order of the 16 choice sets will be randomized within and across choice sets to minimize ordering effects. Participants will view each choice set for as long as they wish. After evaluating choice sets, participants will complete a recall task to assess retention of health warning information and will be provided a debrief page with information about substance use and resources for seeking help with substance use.

Eligibility for participation includes: 1) being 21 years of age or older, 2) being able to speak and understand English, 3) self-reported having consumed cannabis in the last 30 days (any mode, e.g., flower, vape, edible, etc.), and 4) residing in a U.S. state or jurisdiction where retail (i.e., non-medical) cannabis use is legal.

The study population consists of adults aged 21 years and older residing in U.S. states with legal retail cannabis markets (i.e., adult use non-medical or "recreational") who report cannabis use within the past 30 days. Participants will be recruited from an online consumer research panel and will represent active adult cannabis consumers in these jurisdictions.

The data that support the findings of this study are available from the corresponding author upon reasonable request.