Medical cannabis program participation was linked to reduced opioid prescriptions over 18 months in a New York study

Compared to months with no medical cannabis dispensed, a 30-day supply of medical cannabis was associated with 3.53 fewer daily morphine milliequivalents (MME). Mean daily MME decreased from 73.3 at baseline to 57.4 over 18 months of follow-up. The analysis used marginal structural models controlling for unregulated cannabis use.

Prospective cohort study using New York State Prescription Monitoring Program data from September 2018 to July 2023. 204 adults with chronic pain who were prescribed opioids and newly certified for medical cannabis were followed for 18 months. Monthly cannabis dispensation was monitored and linked to opioid prescription data.

Published in JAMA Internal Medicine, this is one of the most methodologically rigorous studies on medical cannabis and opioid substitution. The use of prescription monitoring data (not just self-report) and marginal structural models accounting for unregulated cannabis use strengthens the causal inference.

This JAMA Internal Medicine study adds to growing evidence that medical cannabis programs may support opioid reduction. Uniquely, it accounts for unregulated cannabis use, addressing a major confounder that most previous studies ignored.

Observational cohort without randomization. Bronx, New York setting may not generalize to other populations. Moderate sample of 204 patients. Cannabis dispensation data may not perfectly capture actual consumption. The 3.53 MME reduction, while statistically significant, is modest.