Key Findings

A prospective cohort study published in JAMA Internal Medicine has found that participation in New York State's pharmacist-directed medical cannabis programme was associated with significant reductions in prescription opioid use amongst adults with chronic pain.

The 18-month study tracked 204 adults newly certified for medical cannabis who were already receiving opioid prescriptions. Participants dispensed a 30-day supply of medical cannabis experienced a reduction of 3.53 morphine milligramme equivalents (MME) per day compared to those not dispensed medical cannabis in any given month. Overall, participants' mean daily opioid dose decreased by 22% over the study period, from 73.3 MME to 57.4 MME.

Study Design

The Medical Marijuana and Opioids (MEMO) Study ran from September 2018 through July 2023, recruiting participants from Montefiore Medical Centre and nearby medical cannabis dispensaries in the Bronx, New York.

What makes this study particularly robust is its use of objective data from New York State's Prescription Monitoring Programme (PMP), which tracks all dispensed controlled substances including both opioids and medical cannabis. This allowed researchers to measure actual dispensation patterns rather than relying on self-reporting. The study also controlled for unregulated cannabis use, addressing a key limitation of previous research.

Who Participated

The study population reflected the demographics of chronic pain patients in urban New York. Most participants (55%) were female, with an average age of 57 years. The cohort was ethnically diverse and predominantly economically disadvantaged—78% were unemployed, 78% had only public insurance, and 58% lived below the federal poverty level.

Participants reported substantial pain burdens, rating their pain severity at 6.6 out of 10 on average. Mental health challenges were common, with 46% reporting moderate to severe depression and 37% experiencing PTSD symptoms.

What Patients Actually Used

Amongst the 142 participants who obtained medical cannabis during the study, dispensaries provided 2,832 products over 18 months.

Product preferences broke down as:

• 43% ingested (edibles) or oromucosal (tinctures, oral sprays)
• 33% oils or flower for vaporisation
• 22% flower for combustion

High-THC products dominated (78%), with balanced THC-CBD products (14%) and high-CBD products (8%) making up the remainder.

An important finding: 30% of certified participants never actually obtained cannabis from a medical dispensary, and participation declined over time amongst those who did.

The New York Model

New York's medical cannabis programme stands out for its highly medicalised approach. After physician certification, patients visit medical cannabis dispensaries where pharmacists independently evaluate them, review the certifying clinician's recommendations, and authorise specific products and supply durations.

All dispensations are recorded in the state's Prescription Monitoring Programme alongside other controlled substances. This creates an unusual level of oversight and tracking compared to many medical cannabis programmes globally.

Why This Matters

The 22% reduction in opioid use may seem modest, but researchers emphasise this aligns with current clinical recommendations for gradual opioid tapering over extended periods rather than rapid cessation.

This study stands out because it:

• Followed patients prospectively for 18 months rather than looking backwards
• Used objective prescription monitoring data rather than self-reporting
• Controlled for unregulated cannabis use—a critical factor often ignored in previous research
• Examined an actual medical programme with clinical oversight rather than just comparing states with and without legal cannabis

Limitations

The study's findings may not generalise to states with different medical cannabis laws, rural populations, or patients with acute rather than chronic pain. The research team notes their findings support a medicalised model with pharmacist involvement rather than models where medical and adult-use dispensaries are indistinguishable.

A placebo-controlled randomised trial is currently underway to provide more definitive evidence on whether medical cannabis reduces prescription opioid use.

Implications in an Australian Context

Whilst this study examined New York's specific programme structure, the findings contribute to the growing evidence base for medical cannabis as a potential component of chronic pain management strategies. The pharmacist-directed model and objective dispensation tracking may offer insights for jurisdictions considering programme design, though direct comparisons require careful consideration of differing regulatory frameworks.

Source: Slawek DE, et al. JAMA Internal Medicine, December 8, 2025
DOI: 10.1001/jamainternmed.2025.6496