Evaluating the Impact of Psychotherapeutic Advertising Claims on Cannabis Purchasing

The U.S. legal cannabis industry increasingly uses psychotherapeutic advertising claims (PACs) on its websites to promote products that contain Δ⁹-tetrahydrocannabinol (THC; the primary intoxicant in cannabis) as effective treatments for mental health disorders-most notably depression and anxiety.

PACs employ mental health proxy terms (e.g., happy, calm) and symptoms (e.g., fatigue, stress) to imply or explicitly state that products alleviate specific mental health conditions (e.g., depression, anxiety). Although THC may temporarily relieve such symptoms, long-term use likely exacerbates depression and anxiety. The industry uses PACs to attract newer, less experienced (i.e., infrequent) consumers who often rely on industry-supplied "education" and marketing to make purchase decisions. Consequently, there is a need to examine the impact of PACs on cannabis purchasing among infrequent consumers with mental health symptomatology to understand whether such claims pose a risk of increased THC exposure and potential exacerbation of symptoms.

Warning labels (WLs) are an effective regulatory tool for reducing the purchase and use of harmful products (e.g., tobacco, alcohol, unhealthy foods). The WLs currently used by some U.S. states with legal cannabis focus on generic risks (e.g., "do not operate a motor vehicle") and do not address potential adverse impacts specific to mental health. Prior research has demonstrated that focused warnings about specific negative health effects improve consumer understanding of those effects. The industry's pervasive use of PACs and THC's association with worsened depression and anxiety underscore the need to investigate whether a mental health-focused WL can reduce THC purchasing among consumers with depression and anxiety.

The goal of the proposed project is to determine how PACs and a mental health WL impact cannabis purchase intentions among U.S. adults who are infrequent (1-100 days in the past year) cannabis consumers with symptoms of mild to severe depression and/or generalized anxiety. To achieve this goal, investigators will leverage a realistic online cannabis store platform developed in our laboratory. Participants (N=1,294) from two pilot studies (1) rated the online store as easy to navigate and highly realistic (e.g., realistic product types, potencies, names, prices); (2) rated the PAC stimuli as informative and helpful for making purchase decisions; and (3) spent total amounts on products that closely matched typical spending reported in prior studies.

The proposed between-subjects design study (N=2,000) will randomize participants to shop at one of four versions of the online cannabis store, each varying in the presence or absence of PACs and WLs:

1. Control Claims (CC) Store: includes only claims about a product's sensory (e.g., "Fruity") and quality (e.g., "Organic") attributes-a common alternative type of real-world cannabis advertising.
2. PAC Store: includes CC plus claims about a product's mental health effects (e.g., "Calming") and symptom relief (e.g., "Helps with stress").
3. WL Store: includes CC plus a WL about the negative impact of THC on anxiety and depression.
4. PAC+WL Store: includes PACs, WL, and CC.

Participants will be instructed to browse the store and buy products as if making real purchases. Each store will offer the same 30 products. Our specific aims are to test the effect of each store environment on three primary outcomes: (1) total milligrams of THC (mgTHC) purchased, (2) average potency (%THC) of products purchased, and (3) overall number of products purchased.

AIM 1: Test the effect of PACs on cannabis purchase intentions of infrequent users with anxiety or depression.

Hypothesis 1: Those exposed to the PAC Store will purchase (1) greater total mgTHC, (2) higher potency products, and (3) a greater overall number of products than those exposed to the CC Store.

AIM 2: Test the effect of a mental health WL on cannabis purchase intentions of infrequent users with anxiety or depression.

Hypothesis 2a: Those exposed to the WL Store will purchase (1) fewer total mgTHC, (2) lower potency products, and (3) a smaller number of products than those exposed to the CC Store.

Hypothesis 2b: Those exposed to the PAC+WL Store will purchase (1) fewer total mgTHC, (2) lower potency products, and (3) a smaller number of products than those exposed to PACs without the WL (PAC Store).

AIM 3: Test whether anxiety severity, depression severity, and past-year cannabis use frequency moderate the between-group relationships observed in Aim 1 and Aim 2.

Hypothesis 3: The observed effects of the PAC Store vs. CC Store (Aim 1) and WL Store vs. CC Store (Aim 2) will be greater for those with more severe depression or generalized anxiety and those with less frequent cannabis use. Notably, moderation effects may still exist even if investigators do not observe significant direct relationships as hypothesized in Aims 1 and 2. Thus, the feasibility and importance of testing the Aim 3 hypothesis do not depend on confirming Aims 1 and 2.

This proposal is responsive to NIDA NOT-DA-22-003. With expertise in addictive product advertising, cannabis policy, epidemiology and biostatistics, and co-occurring disorders, our team is uniquely qualified to conduct this project. Results will provide insights into how PACs and WLs alter cannabis purchasing and THC-related risks among novice consumers with anxiety or depression. Such information could help inform targeted regulations to protect this vulnerable group. This study will also lay the groundwork for future Cannabis Regulatory Science research exploring additional factors that influence cannabis purchasing and use patterns (e.g., advertising type, branding, demographics). This programmatic line of research will contribute to evidence-based cannabis policy that balances public health concerns with the evolving legal cannabis market.