Medical Cannabis Laws Combined with Prescription Monitoring Reduced Chronic Pain Outpatient Visits | Research

The takeaway

When states had both prescription drug monitoring programs and medical cannabis laws, Medicaid patients with chronic pain were 19% less likely to have outpatient pain visits, suggesting cannabis may be substituting for some conventional pain treatments.

Chronic pain patients, policymakers studying the intersection of opioid and cannabis policy, and healthcare providers in medical cannabis states.

19% fewer chronic pain outpatient visits where both policies existed

What the researchers found

Prescription drug monitoring programs alone were not associated with changes in chronic pain outpatient visits. However, in states where medical cannabis laws were also present, patients had 19% lower odds of chronic pain-related outpatient visits (aOR = 0.81, 95% CI: 0.71-0.92). Neither policy combination was associated with changes in emergency department visits for chronic pain.

Why it matters

As states have simultaneously tightened opioid prescribing (through PDMPs) and expanded cannabis access, patients with chronic pain are navigating both policy shifts. The reduction in outpatient visits where both policies exist may indicate patients are self-managing pain with cannabis rather than seeking conventional treatment.

The numbers in context

N = 4,878,462 Medicaid enrollees. PDMP + MCL: aOR = 0.81 (95% CI: 0.71-0.92) for outpatient visits. PDMP alone: not significantly associated. Neither combination affected ED visits. Sample: 67.2% female, 51.2% non-Hispanic White, 37.2% aged 40-55.

How the study worked

Researchers created annual cohorts of Medicaid enrollees with chronic pain diagnoses using national Medicaid claims data from 2002-2013 and 2016. Negative binomial hurdle models compared three state-level conditions: no PDMP, PDMP without MCL, and PDMP with MCL. The sample of nearly 4.9 million patients was primarily female (67.2%) and ages 40-55.

What this study cannot tell us

Medicaid claims data cannot determine whether reduced visits reflect improved self-management or disengagement from care. The study period (2002-2016) precedes the major wave of recreational legalization. Cannabis use itself was not directly measured, only inferred from state-level policy.

How to read the evidence

Large-scale Medicaid claims analysis with nearly 5 million patients and appropriate policy-level modeling. Strong population evidence, though cannabis use was inferred rather than directly measured.

When this study was published

Published in 2025 with Medicaid data from 2002-2016.

The bigger picture

This study captures a critical period in U.S. drug policy when prescription monitoring programs were expanding alongside medical cannabis access. The shift away from outpatient pain management in MCL states raises both possibilities and concerns: patients may be finding effective relief through cannabis, or they may be losing connection with clinical pain management.

Questions still open

Are patients in MCL states achieving similar or better pain outcomes despite fewer visits? Does reduced outpatient engagement carry risks of missing other health issues detected during pain visits?

Common questions

Does this mean medical cannabis is replacing pain doctors?

The study found fewer outpatient pain visits in states with medical cannabis access, but it cannot confirm whether patients are using cannabis instead of seeing doctors. The shift could reflect successful self-management or concerning disengagement from care.

What is a prescription drug monitoring program?

PDMPs are state-level electronic databases that track controlled substance prescriptions. They help identify patients receiving opioids from multiple providers and have been linked to reduced opioid prescribing.

Read the original research

The Combined Relationship of Prescription Drug Monitoring Program Enactment and Medical Cannabis Laws with Chronic Pain-Related Healthcare Visits.

Journal of general internal medicine, 40(5), 1030-1038

View on PubMed ↗Publisher’s paper ↗

Citation

Mannes, Zachary L; Nowels, Molly; Mauro, Christine; Cook, Sharon; Wheeler-Martin, Katherine; Gutkind, Sarah; Bruzelius, Emilie; Doonan, Samantha M; Crystal, Stephen; Davis, Corey S; Samples, Hillary; Hasin, Deborah S; Keyes, Katherine M; Rudolph, Kara E; Cerdá, Magdalena; Martins, Silvia S. (2025). The Combined Relationship of Prescription Drug Monitoring Program Enactment and Medical Cannabis Laws with Chronic Pain-Related Healthcare Visits.. Journal of general internal medicine, 40(5), 1030-1038. https://doi.org/10.1007/s11606-024-09053-6