A new study, published recently in the International Journal of Drug Policy, has found that it is unclear whether medical marijuana is effective at treating chronic pain.

The study also found that patients who use daily marijuana for severe pain reported their health had become worse in the last year.

Researchers said the findings do not necessarily mean that marijuana is not at all effective at treating at least some kinds of pain. However, they suggest that more studies are needed before accepting marijuana as an effective therapy for chronic, severe pain.

Study co-author Prof. Bridget Freisthler of Ohio State University said, “It’s not clear if marijuana is helping or not. The benefits aren’t as clear-cut as some people assume.”

Lead author Alexis Cooke of the University of California, San Francisco, said, “One issue is the complex relationship between pain, marijuana use, and self-reported health.”

“Having high chronic pain is related to poorer health, so it may be that people who are using marijuana more often already had worse health, to begin with,” she added. “There are still a lot of questions to answer.”

The findings showed no association between daily marijuana use and change in health status among patients with low levels of pain. However, the daily use of marijuana was associated with worsening health status among patients with high levels of pain.

Freisthler said, “It shows how little we know about marijuana as medicine, how people are using it, the dosages they are receiving and its long-term effects.”

Medical marijuana is commonly prescribed to patients with different types of pain caused by cancer, arthritis, HIV, and nerve pain. Cooke said, “Researchers don’t know if marijuana has different effects on different causes of pain.”

“Chronic pain is also associated with depression and anxiety,” she added. “Marijuana may help with these problems for some people, even if it doesn’t help with the pain.”

Additionally, marijuana has been found to be helpful for people who have lost their appetite because of pain or nausea caused by certain cancer drugs.

Cooke explained, “It may not be the pain that patients are trying to address.”

“The results do suggest we need to know more about the link between marijuana and pain relief,” Freisthler said. Particularly since the opioid crisis, some people have been touting marijuana as a good substitute for opioids for people in pain. But our study suggests we don’t know that marijuana is helping to address pain needs.”