When cannabis use rises among teenagers, it doesn’t just affect a small group of heavy users, it shifts across all users, touching all levels at the same time, according to a study published in the journal Addiction. This means teen cannabis use behaves in much the same way as alcohol consumption has long been known to do.
The research is based on survey data from more than 250,000 Swedish students aged 15 to 18, collected over more than three decades between 1990 and 2023. Researchers looked at how frequently young cannabis users consumed the drug, and how those patterns changed over time.
The headline finding was striking in its consistency: whenever average cannabis use among teenagers went up or down, the change happened in parallel across all groups of users, from those who used occasionally to those who used frequently.
“Increases in average use are not driven solely by a small group of heavy users, but by broader changes in behavior among users in general,” said co-author Thor Norström, Professor Emeritus at the Swedish Institute for Social Research at Stockholm University.
The study also found that when average use increased, the number of teenagers using cannabis very frequently rose sharply too, meaning more young people were at risk of developing cannabis-related problems.
This pattern mirrors what researchers have long observed with alcohol, and supports what is known as the “total consumption model”: when overall use in a population goes up, the number of people at risk of harm rises with it. The model has been highly influential in shaping alcohol policy, and the new findings suggest it may apply equally to cannabis.
The implication for prevention is significant: targeting only the heaviest users is not enough. Because shifts in cannabis use appear to be driven by broader social forces, such as changing attitudes, norms and availability, efforts to reduce harm need to reach the whole population.
“Our results suggest that adolescent cannabis use is characterized by collective changes, in which social networks, norms, and the broader societal climate play an important role,” said co-author Håkan Leifman, researcher at the Department of Clinical Neuroscience at Karolinska Institutet.
The researchers say the findings are especially timely, given that attitudes towards cannabis have been softening in many countries in recent years. Even in Sweden, where cannabis remains illegal, shifting norms could influence how young people behave. “This underscores the importance of a broad public health perspective in preventive efforts targeting cannabis use among young people,” concluded Norström.
Norström T, Leifman H. Does the total consumption model apply to cannabis use?Addiction. 2026. https://doi.org/10.1111/add.70353