PORTLAND, Ore. — Cannabis products can provide short-term benefits for treating chronic pain, but "little else," according to a review of scientific literature conducted by OHSU researchers.
The review, which was published Monday in the Annals of Internal Medicine, also highlights the relatively limited amount of scientific research that has been conducted on cannabis products. The available evidence for the benefits of cannabis is "surprisingly thin," OHSU wrote in a news release.
"In general, the limited amount of evidence surprised all of us," said Dr. Marian S. McDonagh, lead author of the review. "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."
The researchers found very little scientifically valid research into most cannabis products, she said, and the few studies that were available were not designed to answer questions about treating chronic pain.
The upshot of the lack of research is that it's difficult for doctors to guide patients about possible treatments, the authors said.
"Cannabis products vary quite a bit in terms of their chemical composition, and this could have important effects in terms of benefits and harm to patients," said co-author Dr. Roger Chou.
The researchers did find limited evidence that two products made of 100% THC could support short-term benefits for treating neuropathic pain, which is caused by damage to peripheral nerves. A third product that mixed THC and CBD also showed evidence of some clinical benefit.
All three products led to notable side effects, according to the news release, such as sedation and dizziness (which cannabis users would presumably describe as a feature rather than a bug).
OHSU intends the document to be a "living review" that will be updated regularly, according to the press release, and shared on a new web-based tool to help doctors and researchers evaluate the latest evidence about the effectiveness of cannabis.