Plate Nº 36 · recorded October 10, 2026
Health & Medicine ResearchReported finding
US Medical Cannabis Registrations Jumped 420% From 2016 to 2024
US medical cannabis registrations rose from 747,000 in 2016 to 3.9 million in 2024, with PTSD and anxiety citations growing despite limited evidence.
By James Calloway3 min read593 words
In brief
- Registered US medical cannabis patients grew from about 747,000 in 2016 to about 3.9 million in 2024 — a rise of more than 420%.
- Enrollment often declined in states after they legalized recreational cannabis.
- Chronic pain remained the most common reason for medical cannabis use throughout 2016–2024.
- Registrations for PTSD and anxiety grew substantially despite limited supporting evidence.
- The study by Kevin F. Boehnke et al. was published in the Annals of Internal Medicine (DOI: 10.7326/annals-26-01527).
The number of Americans registered to use medical cannabis more than quintupled in eight years, climbing from roughly 747,000 in 2016 to about 3.9 million in 2024 — an increase of more than 420%. That is the headline finding of a national analysis published in the Annals of Internal Medicine by researchers at the University of Michigan.
The study, led by Kevin F. Boehnke and colleagues, examined publicly available medical cannabis registry data from states and the District of Columbia between 2016 and 2024. The team tracked two things: how many patients enrolled in state medical programs, and what medical conditions those patients cited when they registered.
Why did enrollment stop growing in some states?
The overall trend hides an important pattern. Patient enrollment often declined after a state legalized recreational cannabis, the researchers found. The likely explanation: once anyone 21 or older can buy cannabis at a licensed store, some patients stop bothering to register in the medical program and obtain the drug through the recreational market instead.
In other words, medical registries may increasingly undercount actual cannabis use for health purposes in states with broad recreational access. The registry numbers reflect who signs official paperwork, not everyone who uses the drug medicinally.
What are patients using medical cannabis for?
Chronic pain remained the most common reason for medical cannabis use throughout the entire study period. That matters because chronic pain is one of the conditions with the strongest evidence base for cannabis treatment.
But the fastest growth came from elsewhere. Registrations citing mental health conditions — specifically posttraumatic stress disorder (PTSD) and anxiety — grew substantially between 2016 and 2024.
This shift concerns the researchers. Evidence supporting cannabis as a treatment for PTSD and anxiety remains limited, they note, even as growing numbers of patients sign up for exactly those conditions.
What are the study's limitations?
The analysis relies on state registry data, which comes with caveats worth keeping in mind:
- Registry figures capture only enrolled patients, missing users in recreational-legal states who never register.
- State registries differ in what conditions they qualify, how they report data, and how often patients renew.
- The data show correlations — such as enrollment declining after recreational legalization — not proof of why individuals leave medical programs.
The findings are also descriptive. The study documents trends in registration and stated reasons for use; it does not test whether cannabis helps or harms patients with any specific condition.
Why do researchers want more studies?
The authors conclude that although medical cannabis use has expanded dramatically in the United States, a growing share of patients now uses it for conditions with less evidence supporting its effectiveness. That mismatch — expanding use outrunning the science — underscores the need for further research into cannabis's potential benefits and risks, they write.
The pattern is straightforward: the conditions for which evidence is comparatively strong, such as chronic pain, dominate the registries in raw numbers. Yet momentum is shifting toward PTSD and anxiety, where rigorous clinical evidence is thin.
For patients, clinicians, and policymakers, the takeaways are practical. A plateau or decline in a state's medical registry after recreational legalization may say more about access channels than about changing health needs. And rising registrations for mental health conditions signal an urgent need for controlled trials to determine whether cannabis actually helps people with PTSD and anxiety — or exposes them to risk without benefit.
The paper, "Trends in U.S. Medical Cannabis Registrations and Reasons for Use, 2016 to 2024," appears in the Annals of Internal Medicine (DOI: 10.7326/annals-26-01527).
via Medical Xpress (Source)
More from James Calloway
Show full bio
Staff writer covering marketplaces and e-commerce at SciBeat.
205 articles
Nearby plates
- Major Review Links Cannabis Use to Higher Violence Risk
- Cannabis Use Linked to Doubled Violence Risk in Major Review
- Pharmacy Closures Hit Minority Communities Hardest, Study Finds
- Nearly 1 in 3 New Nurse Practitioners Trained at For-Profit Schools
- New CHEST Guideline Targets Smoking Treatment in Hospitalized Patients