Tuesday, July 3, 2018
The huge 2017 National Academies of Sciences report titled "The Health Effects of Cannabis and Cannabinoids: The Current State of Evidence and Recommendations for Research" came to this encouraging conclusion in Chapter 4 of the report concerning the medicinal potential of marijuana: "There is substantial evidence that cannabis is an effective treatment for chronic pain in adults."
A big new study out of Australia, however, now throws some cold water on anyone getting to hot about marijuana's potential as an effective pain reliever. This Business Insider Australia article reports on the study under the headline "A 4-year Australian study of 1500 people finds no evidence that cannabis helps to treat pain." Here are excerpts:
A long term study by the University of NSW — one of the world’s longest in-depth community studies on pharmaceutical opioids and non-cancer pain — has found little evidence to support the use of cannabis in the treatment of chronic pain.
The four-year study of more than 1,500 Australians prescribed opioids for non-cancer pain suggest that there is a need for caution in using medicinal cannabis. Those in the study who used cannabis, and there were many among those with chronic non-cancer pain who had been prescribed opioids, actually had greater pain, anxiety and were coping less....
“Chronic non-cancer pain is a complex problem,” says Dr Gabrielle Campbell at the University of NSW, the lead author in the latest study. “For most people, there is unlikely to be a single effective treatment. In our 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.”
The Pain and Opioids IN Treatment (POINT) study, published today in the journal Lancet Public Health, looked at the effect of cannabis on pain, on the extent to which this interfered with everyday life, and on prescribed opioid use.
In the study, funded by the National Health and Medical Research Council and led by the National Drug and Alcohol Research Centre at UNSW Sydney, participants were recruited through community pharmacies and completed comprehensive assessments of their pain, physical and mental health, medication and cannabis.
Participants had been in pain for a median of 10 years and taken prescribed opioids for for four years. There were very high rates of physical and mental health problems. At each assessment, participants who were using cannabis reported 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. However, the users thought otherwise. Those who used cannabis, despite the study finding no evidence, reported that cannabis was effective (mean score of 7 out of 10). One possibility is that cannabis improves sleep, which in turn improves well-being, say the researchers.
The researchers say double-blind randomised placebo-controlled clinical trials are needed to better understand the impact of cannabis.
The full study being reported on is titled "Effect of cannabis use in people with chronic non-cancer pain prescribed opioids: findings from a 4-year prospective cohort study," and it is available at this link. Reading the abstract makes clearer that this study was entirely observational in that participants were acquiring and using marijuana on their own and reporting that use rather than being giving marijuana in a controlled setting.
Among other reactions, this new study reinforces my sense that we need a lot more studies to really get a handle on the possible value of marijuana to help address the "complex problem" of chronic pain. I am also struck by the line I emphasized above that indicate that a significant majority of marijuana users in the study believed that they were helped by marijuana when the evidence suggested otherwise. A real interesting philosophical issue arises, for the medical profession and for governments, if it turns out that marijuana does not really help many chronic pain problems, but many users think that it does and are eager to have access to the drug because others report that it provides them relief.