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Study breakdown

Cannabis Legalization Linked to Greater Increase in Cannabis Use Disorder Among Veterans With Chronic Pain

evidence
The takeaway

Medical and recreational cannabis laws were associated with significantly greater increases in cannabis use disorder among VA patients with chronic pain than those without, especially ages 65-75.

Pain medicine specialists, VA healthcare providers, and cannabis policy researchers.

19.4% attributable to RCL

of CUD increase among chronic pain patients aged 65-75 in recreational cannabis law states

What the researchers found

Among patients with chronic pain, MCL led to 0.14% and RCL to 0.19% absolute increases in CUD prevalence, with 8.4% and 11.5% of total increases attributable to legalization. Effects were significantly greater than in patients without pain.

Why it matters

Chronic pain patients are increasingly turning to cannabis as opioid prescriptions decline, but they face higher CUD risk, creating a public health concern that grows as legalization expands.

The numbers in context

Yearly n=3.2M-4.6M VHA patients (2005-2019). Pain patients: MCL +0.14%, RCL +0.19% CUD increase. No-pain patients: MCL +0.037%, RCL +0.042%. Ages 65-75 with pain: 19.4% of CUD increase attributable to RCL.

How the study worked

Staggered-adoption difference-in-difference analysis of VHA electronic health records (2005-2019), stratified by chronic pain status with state and year fixed effects and demographic covariates.

Who was studied

U.S. Veterans Health Administration patients aged 18-75 with and without chronic pain (yearly n=3.2M-4.6M, 2005-2019).

What this study cannot tell us

Observational design cannot prove legalization caused CUD increases. VHA patients are predominantly male and may not represent general population. CUD diagnosis rates may reflect increased screening rather than true prevalence increases.

How to read the evidence

Large-scale quasi-experimental design with staggered adoption providing strong observational evidence.

When this study was published

Covers 15 years of VHA data (2005-2019) across changing state cannabis laws.

The bigger picture

As U.S. opioid prescribing declines and cannabis legalization expands, chronic pain patients may substitute cannabis for opioids. While cannabis has a better mortality profile, CUD carries significant impairment and comorbidity.

Replication

Companion to RTHC-04614 and RTHC-04615; findings consistent across related analyses.

Funding

Not specified in abstract

Conflicts of interest

Not specified in abstract

Questions still open

  • Is cannabis substitution for opioids a net positive or negative for chronic pain patients?
  • Should cannabis legalization legislation include specific protections for chronic pain populations?

Read the original research

Chronic Pain, Cannabis Legalization and Cannabis Use Disorder in Veterans Health Administration Patients, 2005 to 2019.

medRxiv : the preprint server for health sciences

Citation

Hasin, Deborah S; Wall, Melanie M; Alschuler, Dan; Mannes, Zachary L; Malte, Carol; Olfson, Mark; Keyes, Katherine M; Gradus, Jaimie L; Cerdá, Magdalena; Maynard, Charles C; Keyhani, Salomeh; Martins, Silvia S; Fink, David S; Livne, Ofir; McDowell, Yoanna; Sherman, Scott; Saxon, Andrew J. (2023). Chronic Pain, Cannabis Legalization and Cannabis Use Disorder in Veterans Health Administration Patients, 2005 to 2019.. medRxiv : the preprint server for health sciences. https://doi.org/10.1101/2023.07.10.23292453