Impact of Delta-8-THC warning labels on perceived intoxication, harm, and susceptibility among adolescents.
Alyssa F. Harlow, Adam M. Leventhal, Jessica L. Barrington‐trimis
The International journal on drug policy May 2025 DOI: 10.1016/j.drugpo.2025.104781 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Mixed within-between-subject randomized experiment embedded in a survey Peer reviewed |
|---|---|
| Sample size | 3,647 |
| Population | Southern California adolescents surveyed in 2023 |
| Topics | Cannabis |
| Keywords | Delta-8-THC Experiment Hemp Warning labels |
| Key findings | Larger warning labels on delta-8-THC products increased adolescents' anticipated intoxication (mean difference 2.50 on a 100-point scale) and perceived harm relative to unmodified products, with no effect on susceptibility to use. Effects on perceived harm were stronger for gummies than vapes and for never versus ever cannabis-using youth. The authors argue states should consider delta-8-THC labeling requirements. |
Abstract
Youth use of hemp-derived cannabis products containing psychoactive Δ8-tetrahydrocannabinol (delta-8-THC) is prevalent in the United States (US). Delta-8-THC is intoxicating, however delta-8-THC products are not subject to warning labeling requirements in many US states. This experiment determined effects of hypothetical cannabis warning labels on perception of delta-8-THC gummies and vape products. A mixed within-between-subject experiment was embedded into a 2023 survey of 3,647 Southern California adolescents. Participants were randomized to view photos of delta-8-THC edible and vape products under one of three conditions (control [unmodified] vs. standard size warning label [universal cannabis warning symbol, government warning text, instructions for use, and text stating it was cannabis-infused] vs. larger warning label [same as standard label with larger cannabis warning symbol]). After image exposure, we measured anticipated intoxication, perceived harm, and susceptibility to use the respective delta-8-THC products. Moderation by product type and cannabis use status were assessed. Youth who viewed delta-8-THC products with larger warning labels (vs. control) reported greater anticipated intoxication (Mean Difference[MD]==2.50, 95 %CI=0.85-4.14 on 100-point scale), and higher likelihood that delta-8-THC products are bad for their health (Risk Ratio[RR]=1.07, 95 %CI=1.02-1.12), pose at least some risk (RR=1.03, 95 %CI: 1.01-1.05), and are the same or more harmful than marijuana (RR=1.04, 95 %CI=1.01-1.07). There were no warning label effects on susceptibility and minimal differences across outcomes between larger versus standard warning labels. Warning label effects on perceived harm were stronger for delta-8-THC gummies (vs. vape) and for never vs. ever cannabis-using youth (interaction p-values < 0.05). Requiring delta-8-THC products to conform to labeling requirements for cannabis products may increase understanding of their intoxicating effects and harm among cannabis-naïve youth. In lieu of federal regulations, states should consider implementation of delta-8-THC regulations such as labeling requirements that promote safety and reduce potential harm to youth.
Comparable studies
Other randomized controlled trials on cannabis, most cited first.
| Study | Year | Design | Participants |
|---|---|---|---|
| Cannabidiol inhibits THC-elicited paranoid symptoms and hippocampal-dependent memory impairment Healthy participants | 2012 | Randomized controlled trial | n = 48 |
| Distinct Effects of Δ9-Tetrahydrocannabinol and Cannabidiol on Neural Activation During Emotional Processing Healthy, English-native, right-handed men who had used cannabis 15 times or less in... | 2009 | Double-blind, randomized, placebo-controlled crossover trial | n = 15 |
| Acute Effects of a Single, Oral dose of d9-tetrahydrocannabinol (THC) and Cannabidiol (CBD) Administration in Healthy Volunteers Healthy male subjects | 2012 | Randomized controlled trial | n = 16 |
| Modulation of Mediotemporal and Ventrostriatal Function in Humans by Δ9-Tetrahydrocannabinol Healthy, native English-speaking, right-handed men of white race/ethnicity who had used... | 2009 | Randomized controlled trial | n = 15 |
| Cannabidiol (CBD) content in vaporized cannabis does not prevent tetrahydrocannabinol (THC)-induced impairment of driving and cognition Healthy volunteers with a history of light cannabis use | 2019 | Randomized, double-blind, within-subjects crossover | n = 14 |