Most people are poorly informed about cannabis health risks, especially psychosis
Across over 72,000 respondents in the U.S. and Canada, only 23-37% knew about cannabis's link to psychosis, while 12-18% believed the false claim that cannabis can cure cancer.
Quick Facts
What This Study Found
Knowledge of cannabis health risks was highest for driving impairment (66-80%), pregnancy risks (61-71%), and addiction potential (51-62%), but lowest for psychosis and schizophrenia risk (23-37%). 12-18% agreed cannabis could cure or prevent cancer (false), and 6-7% believed it could cause diabetes (false). Canadians had the highest health knowledge, followed by U.S. legal states, then U.S. illegal states.
Key Numbers
72,459 respondents. Driving risk awareness: 66-80%. Pregnancy risk: 61-71%. Addiction: 51-62%. Psychosis: 23-37%. False cancer cure belief: 12-18%. False diabetes belief: 6-7%.
How They Did This
Cross-sectional online surveys from the 2018-2019 International Cannabis Policy Study with 72,459 respondents aged 16-65 recruited from Nielsen panels across Canada and U.S. states. Nine health effect questions including two false control items.
Why This Research Matters
Substantial knowledge gaps, particularly about psychosis risk, could lead to uninformed decisions about cannabis use. Frequent consumers had the lowest knowledge despite the greatest exposure.
The Bigger Picture
The finding that Canadian respondents (where cannabis is federally legal with regulated information) had higher health knowledge than U.S. respondents suggests legalization with public education may improve awareness.
What This Study Doesn't Tell Us
Non-probability sampling. Online survey may underrepresent certain populations. Self-reported knowledge may not reflect actual understanding.
Questions This Raises
- ?Could better psychosis risk communication change cannabis use patterns?
- ?Why do frequent users have less health knowledge despite more exposure to cannabis information?
Trust & Context
- Key Stat:
- Only 23-37% knew about cannabis-psychosis link; 12-18% believed cannabis cures cancer
- Evidence Grade:
- Very large international sample, though non-probability online panel methodology limits representativeness.
- Study Age:
- Published in 2022 with 2018-2019 survey data.
- Original Title:
- Perceptions of the health risks of cannabis: estimates from national surveys in Canada and the United States, 2018-2019.
- Published In:
- Health education research, 37(2), 61-78 (2022)
- Authors:
- Goodman, Samantha(6), Hammond, David(36)
- Database ID:
- RTHC-03881
Evidence Hierarchy
A snapshot of a population at one point in time.
What do these levels mean? →Frequently Asked Questions
What did people know least about?
The risk of psychosis and schizophrenia from cannabis use was the least known health risk, with only 23-37% of respondents aware of this association.
Did legalization improve health knowledge?
Yes. Canadian respondents (federal legalization with regulated products and information) had the highest health knowledge, followed by U.S. legal states, then illegal states.
Read More on RethinkTHC
- 420-sober-survival-guide
- CBT-cannabis-recovery
- cannabis-relapse-cycle-pattern
- cold-turkey-vs-taper-quit-weed
- dating-sober-after-quitting-weed
- exercise-quitting-weed-anxiety-brain
- grieving-quitting-weed-loss
- help-someone-quit-weed
- how-to-quit-weed
- journaling-weed-withdrawal
- marijuana-anonymous-SMART-recovery-compare
- meditation-mindfulness-weed-withdrawal
- partner-still-smokes-weed
- partner-still-smokes-weed-quitting
- pink-cloud-sobriety-cannabis
- quit-weed-cold-turkey
- quit-weed-or-cut-back-which-is-better
- quit-weed-regret-went-back
- quitting-weed-20s
- quitting-weed-30s
- quitting-weed-after-years
- quitting-weed-during-crisis-divorce-job-loss
- quitting-weed-exercise
- quitting-weed-grief-loss-coping
- quitting-weed-legal-state
- quitting-weed-success-stories
- quitting-weed-triggers-environment
- relapsed-smoking-weed-what-to-do
- relapsed-weed
- should-i-quit-weed
- sober-music-festival-concert-without-weed
- supplements-weed-withdrawal
- telling-friends-quitting-weed
- weed-relapse-prevention-plan
- weed-relapse-why-it-happens
- weed-ritual-replacement
- weed-ruined-relationships
- weed-social-media-triggers-quit
Cite This Study
https://rethinkthc.com/research/RTHC-03881APA
Goodman, Samantha; Hammond, David. (2022). Perceptions of the health risks of cannabis: estimates from national surveys in Canada and the United States, 2018-2019.. Health education research, 37(2), 61-78. https://doi.org/10.1093/her/cyac006
MLA
Goodman, Samantha, et al. "Perceptions of the health risks of cannabis: estimates from national surveys in Canada and the United States, 2018-2019.." Health education research, 2022. https://doi.org/10.1093/her/cyac006
RethinkTHC
RethinkTHC Research Database. "Perceptions of the health risks of cannabis: estimates from ..." RTHC-03881. Retrieved from https://rethinkthc.com/research/goodman-2022-perceptions-of-the-health
Access the Original Study
Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.
This study breakdown was produced by the RethinkTHC research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.