Nearly 4 Million Medical Marijuana Patients Now Registered Across U.S. States

Nearly 4 Million Patients Registered Nationwide

Nearly 4 million patients are registered to use medical marijuana under state laws in the U.S., according to a pair of new studies published by the American College of Physicians. The research also counted at least 35,000 doctors and clinicians approved to recommend cannabis and nearly 110,000 caregivers authorized to assist patients.

The studies, conducted by researchers with the University of Michigan, were published in the Annals of Internal Medicine. The number of registered patients more than quintupled from about 747,000 in 2016 to approximately 3.9 million in 2024.

However, patient registration has “flattened since 2022, likely influenced by the growing number of jurisdictions with recreational cannabis laws,” one of the papers published in the Annals of Internal Medicine said.

The researchers said declining growth in medical marijuana enrollment is likely tied to many states enacting broader adult-use legalization laws. “Decreased patient enrollment in recreational jurisdictions may result from patients opting out due to licensing fees or inconvenience, privacy concerns, and their use of recreational products for medical purposes without licensure,” they said.

Chronic pain was the most common qualifying condition, accounting for 65 percent of all patient-reported conditions. It was followed by PTSD at 29 percent and anxiety at 17 percent.

Clinicians and Caregivers

A separate paper from the same research team found the number of clinicians authorized to recommend medical marijuana grew from nearly 31,000 in 2020 to almost 36,000 in 2024.

States with only medical cannabis had “substantially lower” rates of authorized clinicians than states that also have recreational marijuana laws. This “may reflect their longer-standing medical cannabis programs, which may foster greater clinical acceptance of cannabis authorization,” the researchers said.

The team also conducted what they described as the first-ever analysis of caregivers authorized under state laws to assist medical cannabis patients. These caregivers help patients grow, obtain and use their medicine.

“There were higher caregiver rates in recreational jurisdictions compared with medical-only jurisdictions and higher caregiver rates in jurisdictions allowing home cultivation compared with those that did not,” the study said.

“Overall, there were approximately 3-fold higher number and 4-fold higher rate of caregivers per patient than authorizing clinicians,” the study said, noting caregivers can purchase, grow and produce cannabis for patients services authorized clinicians cannot legally provide.

Research Methods and Limitations

For both studies, researchers analyzed medical cannabis data using publicly available reports, registry websites, data requests and communications with regulators overseeing state marijuana programs.

The authors cautioned that the research has limitations, including the inconsistency with which state officials track and report data about their respective medical cannabis programs.

The “widespread use” of medical cannabis “reflects the importance of continued rigorous clinical investigations of cannabis products in these conditions and more broadly to better understand possible risks and benefits,” the authors said.

The studies were published by the American College of Physicians and appear in the Annals of Internal Medicine.

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