Are cannabis effective in reducing chronic pain?

Medicinal cannabis are not as effective at relieving chronic non-cancer pain as commonly assumed, suggests a four-year study, challenging the previously known belief.

The use of cannabis for medicinal purposes has been increasing worldwide and there has been speculation that using cannabis for pain may also allow people to reduce their prescribed opioid use.

However, the study published in the journal Lancet Public Health, found no evidence suggesting that cannabis use improved patient outcomes, reduced pain severity or exerted an opioid-sparing effect.

"Chronic non-cancer pain is a complex problem. For most people, there is unlikely to be a single effective treatment," said lead author Gabrielle Campbell from University of New South Wales in Sydney, Australia.

"In the study of people living with chronic non-cancer pain who were prescribed pharmaceutical opioids, despite reporting perceived benefits from cannabis use, we found no strong evidence that cannabis use reduced participants' pain or opioid use over time," Campbell explained.

For the study, the team examined data from 1,514 participants for four years who completed a baseline interview.

The participants who were using cannabis reported over a series of assessments that they were experiencing greater pain and anxiety, were coping less well with their pain and reported that pain was interfering more in their life, compared to those not using cannabis.

There was no clear evidence that cannabis led to reduced pain severity or pain interference or led participants to reduce their opioid use or dose, the results suggested.