Evidence-Based Cannabis Research
Cannabis is often presented as harmless, or even beneficial, yet the scientific record points to serious and wide-ranging harms. From mental health and violence to birth defects and environmental damage, the evidence challenges the popular narrative around legalisation and normalisation.
This collection gathers peer-reviewed studies, expert summaries, and explainer videos that together build a clear, evidence-based picture of cannabis-related harm. The resources are grouped by theme so readers can move straight to the area most relevant to them.
Resources
Epidemiology
Population-level research mapping the disease burden linked to cannabis, including cancers and birth defects, alongside summaries from leading epidemiologists.
- Cannabis and Hemp Scientific Review
- World Expert Dr Reece – Summary of Cannabis Epidemiology (opens in a new tab)
- Cannabis and Cancers – Europe (opens in a new tab)
- Cannabis as the New Thalidomide (opens in a new tab)
- Cannabis and Cancers – USA
Resources
Cannabis and Violence
Studies examining the relationship between cannabis use and violent behaviour, including mass violence and violence between intimate partners.
Resources
Cannabis and the Environment
Cannabis cultivation carries a significant and often overlooked environmental cost. This research looks at its impact on water and wildlife.
Resources
Cannabis and Children
Evidence on how cannabis affects children, from developmental damage to accidental poisoning in the home.
Resources
Cannabis, Workplace and Secondhand Smoke
How cannabis affects safety in the workplace and the health of bystanders exposed to secondhand smoke.
Resources
Cannabis – Social Justice Considerations
An examination of the social-justice arguments frequently used to support changes to cannabis policy.
Resources
Cannabis Science Videos
Short, accessible videos that summarise the documented harms of cannabis for a general audience.
Why This Matters
Sound drug policy depends on an honest reading of the science. The studies and summaries gathered here show that the harms of cannabis are real, measurable, and far-reaching. OVOM shares them to support prevention-focused policy and to help families, educators, and decision-makers stay informed.