In a systematic review performed by researchers at Oregon Health & Science University and published in Annals of Internal Medicine, evidence supporting the effectiveness of cannabis-related products for treating pain was found to be surprisingly thin, despite the rising popularity of these products.
Researchers found some evidence to support cannabis-related products in treating neuropathic pain, or pain caused by damage to peripheral nerves. These products also led to notable side effects, including sedation and dizziness, however.
Out of 3,000 published studies examined in the review, only 25 were found to contain “scientifically valid” evidence.
“In general, the limited amount of evidence surprised all of us,” says lead author Marian S. McDonagh, PharmD, emeritus professor of medical informatics and clinical epidemiology in the OHSU School of Medicine. “With so much buzz around cannabis-related products, and the easy availability of recreational and medical marijuana in many states, consumers and patients might assume there would be more evidence about the benefits and side effects.
“Unfortunately, there is very little scientifically valid research into most of these products,” she says. “We saw only a small group of observational cohort studies on cannabis products that would be easily available in states that allow it, and these were not designed to answer the important questions on treating chronic pain.”
The review will be updated on an ongoing basis to help researchers evaluate the latest evidence around the health effects of cannabis. Dubbed Systematically Testing the Evidence on Marijuana (STEM), the living review will be shared on a new web-based tool launched by OHSU and VA Portland Health Care System this year.
Read the full study online at https://doi.org/10.7326/M21-4520.
