US medical cannabis patients increased 33% from 3.1 million (2020) to 4.1 million (2022), but 13 of 15 recreational states saw enrollment declines, and the proportion of patients using cannabis for conditions with strong evidence decreased.
Medical cannabis policy makers, healthcare providers authorizing cannabis, public health researchers
4.1 million patients; evidence-based conditions declining
What the researchers found
Enrolled patients grew from 3,099,096 (2020) to 4,132,098 (2022), a 33.3% increase. Population prevalence: 175 to 215 per 10,000. But 13/15 adult-use states had decreased enrollment. Evidence-supported qualifying conditions dropped from 70.4% to 53.8%. Chronic pain was the top condition (48.4%), followed by anxiety (14.2%) and PTSD (13.0%). 29,500 authorizing clinicians (7.7 per 1,000 patients).
Why it matters
The shift toward conditions without strong evidence support suggests medical cannabis programs are expanding into areas where therapeutic value is unproven. Combined with declining enrollment in recreational states, this paints a complex picture of medical cannabis in the US.
The numbers in context
4.13 million patients in 2022 (215 per 10,000). 33.3% growth from 2020. 13/15 recreational states had declines. Evidence-supported conditions: 70.4% to 53.8%. Chronic pain: 48.4%. Anxiety: 14.2%. PTSD: 13.0%. 29,500 clinicians (53.5% physicians).
How the study worked
Ecological study analyzing publicly available state medical cannabis registry data from 2020-2022 across 39 jurisdictions. Assessed patient volume, qualifying conditions, and authorizing clinician characteristics.
What this study cannot tell us
Missing data from major states including California. Descriptive analysis without causal modeling. Cannot assess individual use patterns. Qualifying conditions may not reflect actual reasons for use. Data reporting varies by state.
How to read the evidence
National registry data published in Annals of Internal Medicine provides authoritative trends, limited by state-level reporting variability.
When this study was published
2024 analysis of US state registry data from 2020-2022
The bigger picture
The US medical cannabis landscape is bifurcating: growing in medical-only states while shrinking in recreational states, with an increasing proportion of patients using cannabis for conditions where the evidence base is limited.
Questions still open
- Should medical cannabis qualifying conditions require stronger evidence support? How should medical programs adapt in states that also allow recreational use?
Common questions
How many Americans have medical cannabis cards?
What are people using medical cannabis for?
Read the original research
Trends in U.S. Medical Cannabis Registrations, Authorizing Clinicians, and Reasons for Use From 2020 to 2022.
Annals of internal medicine, 177(4), 458-466
Citation
Boehnke, Kevin F; Sinclair, Rachel; Gordon, Felicia; Hosanagar, Avinash; Roehler, Douglas R; Smith, Tristin; Hoots, Brooke. (2024). Trends in U.S. Medical Cannabis Registrations, Authorizing Clinicians, and Reasons for Use From 2020 to 2022.. Annals of internal medicine, 177(4), 458-466. https://doi.org/10.7326/M23-2811
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