WHO Updates Cannabis Risk Assessment for First Time in Decade

WHO Expert Committee Completes Multi-Year Review Process

The WHO Expert Committee on Drug Dependence completed its cannabis risk assessment after a three-year evidence review spanning clinical trials, epidemiological data, and regulatory outcomes from 73 member states. The committee convened in Geneva from June through August 2026 to finalize recommendations that will inform United Nations drug scheduling decisions and national policy frameworks.

The last comprehensive WHO cannabis assessment occurred in 2016. Back then, 11 countries had legalized medical cannabis and two had authorized adult use. As of August 2026, 47 countries permit medical cannabis programs and 12 have enacted recreational legalization frameworks, according to the International Narcotics Control Board.

Dr. Mariângela Simão, WHO Assistant Director-General for Access to Medicines and Health Products, led the assessment process. The committee reviewed 2,847 peer-reviewed studies published between 2016 and 2026, focusing on dependency profiles, therapeutic applications for chronic pain and epilepsy, and adolescent neurodevelopmental impacts.

Key Findings on Dependency and Therapeutic Use

The assessment found that approximately 9 percent of adult cannabis users develop dependency, a rate lower than alcohol (15 percent) and tobacco (32 percent) but higher than the 2016 estimate of 7 percent. The increase reflects refined diagnostic criteria in the DSM-5-TR and longitudinal cohort data from legalized markets in Canada, Uruguay, and 24 U.S. states.

For therapeutic applications, the committee identified moderate-to-strong evidence supporting cannabis-based medicines for chemotherapy-induced nausea, multiple sclerosis spasticity, and treatment-resistant epilepsy. Cannabidiol formulations carry minimal dependency risk. THC-dominant products present measurable but manageable abuse potential when prescribed under medical supervision.

The WHO analysis distinguished between whole-plant cannabis, pharmaceutical-grade extracts, and synthetic cannabinoids, assigning different risk profiles to each category based on standardization and potency control.

Adolescent use patterns drew particular scrutiny. Regular cannabis use before age 18 correlates with increased risk of anxiety disorders, academic underperformance, and later substance use, though causality remains difficult to isolate from confounding socioeconomic and genetic factors.

Implications for UN Drug Scheduling and National Policy

The updated assessment will inform the United Nations Commission on Narcotic Drugs when it reviews cannabis scheduling under the 1961 Single Convention on Narcotic Drugs during its March 2027 session. The WHO previously recommended in 2019 that the Commission remove cannabis and cannabis resin from Schedule IV, the most restrictive category reserved for substances with high abuse potential and no therapeutic value. That recommendation passed by a narrow 27-25 vote among member states in December 2020.

The 2026 assessment doesn't include explicit scheduling recommendations, according to a WHO spokesperson. Instead, it provides an evidence base for member states to evaluate their domestic frameworks. The report acknowledges that cannabis policy involves considerations beyond public health—criminal justice reform, economic regulation, and social equity among them.

Countries with established legal markets are expected to cite the assessment when justifying regulatory decisions to international bodies. Canada, Germany, and Thailand have already referenced preliminary WHO findings in submissions to the International Narcotics Control Board defending their legalization programs.

What Policymakers and Operators Should Watch

The WHO assessment arrives as the United States Drug Enforcement Administration conducts its own rescheduling review, with a final rule on moving cannabis from Schedule I to Schedule III expected by December 2026. The WHO report doesn't bind U.S. agencies. Still, federal regulators historically align risk assessments with international scientific consensus to maintain treaty compliance.

For cannabis operators, the updated WHO guidance strengthens the case for medical programs while underscoring the need for age restrictions, potency labeling, and dependency screening in adult-use markets. Jurisdictions that have delayed legalization—including most of the European Union, Japan, and South Korea—may use the assessment to justify cautious pilot programs rather than broad prohibition.

The full WHO assessment, including appendices on specific cannabinoids and delivery methods, is available through the organization's technical report series. Member states have until November 2026 to submit formal comments before the findings are incorporated into the March 2027 Commission on Narcotic Drugs agenda. For ongoing coverage of international cannabis policy developments, see the CannIntel topic hub on WHO cannabis assessment.