A study published October 19, 2026, in the Journal of Cannabis Research examined whether cannabis use disorder was associated with venous blood clots in U.S. medical records.
After matching adults diagnosed with cannabis use disorder to a comparison group, researchers found no statistically significant association with venous blood clots over a 10-year follow-up window.
What the Researchers Compared
The analysis compared 5,031 adults diagnosed with cannabis use disorder with 5,031 matched controls. Matching helped account for measured differences between the groups, including other health conditions and substance use.
The initial association weakened after matching, showing why the way researchers compare patients matters when interpreting cannabis findings.
What “No Significant Association” Means
The result means the matched analysis did not find sufficient statistical evidence of an association. It does not prove there is no risk. A modest effect could still remain undetected.
The Study’s Limits
- This was an observational study, so it cannot establish cause and effect or prove cannabis is safe.
- The study focused on people diagnosed with cannabis use disorder. Its findings should not be generalized to all cannabis consumers.
- The findings do not establish safety in surgery or trauma, or answer separate questions about heart attacks and strokes.
Why It Matters for Cannabis Education
Credible cannabis education requires looking beyond headlines. Understanding how researchers account for other health factors, and acknowledging what remains uncertain, helps people interpret evidence without overstating either benefits or harms.