Swedish Cannabis Use Underestimated: Implications for Policy Reform

Swedish Study Reveals Substantial Underreporting of Cannabis Use

A 2026 population-based thesis from Sweden demonstrates that cannabis use and cannabis use disorder (CUD) are significantly underestimated by traditional survey methods, particularly among young adults. Using both direct and indirect survey techniques, the research found that indirect methods like the randomized response technique produced much higher estimates of cannabis use than standard surveys, with differences especially pronounced among men, students, and unemployed individuals. This underestimation is not trivial: survey-based estimates suggest the actual burden of CUD could be up to 25 times higher than what is recorded in Swedish healthcare system diagnoses.

Mechanisms: Survey Methods and Healthcare Utilization

Indirect survey methods, such as the randomized response technique, reduce social desirability bias and legal concerns, leading to more accurate self-reporting of illicit drug use. In this Swedish study, these methods revealed a much higher prevalence of both lifetime and recent (past 12-month, past 30-day) cannabis use than traditional surveys. The research also incorporated systematic review and prediction modeling, showing that decriminalization in other countries has often led to increased use and, in some cases, greater healthcare utilization for acute intoxication, pediatric exposures, and cannabis-related psychosis. However, the study found no clear evidence that decriminalization alone increases the prevalence of cannabis use disorder, highlighting the complexity of policy effects.

Policy and Research Implications: Preparing for Regulatory Change

Accurate prevalence estimates are essential for effective drug policy and healthcare planning, especially as Sweden and other jurisdictions debate potential reforms such as decriminalization. This thesis underscores that traditional surveillance systems may dramatically underestimate both cannabis use and associated healthcare needs. Policymakers considering regulatory changes for cannabis—or for other controlled substances, including psychedelics—must account for the likelihood that official statistics understate the true scope of use and treatment demand. One non-obvious implication is that healthcare systems may be even less prepared for increased demand following policy change than current models predict, due to systematic undercounting of baseline prevalence.

• Survey Methodology: The choice of survey method has a profound impact on measured prevalence, with indirect methods revealing much higher rates of use.
• Healthcare Capacity: The gap between predicted and observed CUD cases suggests significant unmet treatment needs, which could strain healthcare resources if policy becomes more permissive.
• Policy Modeling: Models predicting the impact of decriminalization must adjust for underreporting in baseline data to avoid underestimating future healthcare demand.

Risks, Unknowns, and Cautions for Future Research

Traditional surveillance systems likely underestimate both cannabis use and cannabis-related healthcare needs, which poses risks for policy implementation and resource allocation. There is also uncertainty around the causal relationship between decriminalization and increases in problematic use or healthcare utilization. While the study found increased use and healthcare visits post-decriminalization in some countries, it did not find clear evidence of increased CUD prevalence. This distinction is critical for policymakers to understand the nuanced effects of legal change. Additionally, the Swedish context—where cannabis remains illegal—may not generalize directly to jurisdictions with different cultural or legal environments.

Looking Ahead: Lessons for Broader Drug Policy Reform

As Sweden and other countries consider regulatory changes for cannabis and potentially other controlled substances, this research highlights the urgent need for improved surveillance methods and proactive healthcare planning. For psychedelic policy and research, the Swedish experience serves as a cautionary tale: underestimating baseline use and treatment needs can undermine both public health and policy objectives. Future studies should prioritize indirect survey techniques and integrate healthcare utilization data to provide a more accurate foundation for policy decisions. The thesis also invites further research into why so few individuals with CUD are diagnosed or treated, pointing to potential barriers in healthcare access, stigma, or provider training.

How we research: This article was written by Dr. Erik Sandström, MSc, PhD (Public Health Epidemiology), and reviewed by Dr. Karin Olsson, MD, on 2026-10-12. Primary source: OpenAlex Thesis W7221117550.