SAN DIEGO, Calif. — Adolescents in California consistently perceive cannabis as less harmful than other commonly used substances, according to a new study analyzing data from two large statewide school surveys. Shu-Hong Zhu, PhD, professor at the UC San Diego Herbert Wertheim School of Public Health and Human Longevity Science, and co-authors examined how teens view the risks of everyday and occasional use of cannabis compared to alcohol, nicotine vapes, and cigarettes, drawing on responses from more than 175,000 students across surveys conducted in 2019–2020 and 2024.
The findings show a clear and persistent pattern: Cannabis is viewed as the least harmful substance among respondents. In the earlier survey, about two-thirds of adolescents considered regular cannabis use harmful, compared to higher proportions for alcohol, vaping, and cigarettes. While perceptions of harm were lower across all substances for occasional use, cannabis remained the least concerning to teens. These trends held steady in the 2024 data, suggesting that adolescents’ relatively low perception of cannabis-related risk has remained consistent over time.
The study also identified important differences based on age, experience, and social environment. Unlike alcohol and tobacco products — where perceived harm generally stayed the same or increased with grade level — perceptions of cannabis risk declined as students got older. Younger adolescents were more likely to view cannabis as harmful, but this perception weakened significantly by 12th grade. Additionally, teens who had used a substance were less likely to view it as harmful, with the largest perception gap observed for cannabis. Peer influence played a major role as well: Adolescents with more friends who used a substance consistently rated it as less harmful, with the strongest effect again seen for cannabis.
These findings raise concerns for public health, as lower perceived risk is often associated with higher likelihood of use. Although overall adolescent cannabis use has declined in recent years, researchers note that it remains a concern due to potential impacts on brain development, cognition and mental health. The authors suggest that prevention and education efforts may need to better address cannabis-specific risks, particularly as shifting social norms and increased exposure to pro-cannabis messaging may be influencing how young people perceive its safety.
The study published on May 5, 2026 in Drug and Alcohol Dependence.
