In a new study published in Lancet Public Health, University of NSW researchers found that cannabis consumption might not be the opioid-alternative painkiller that so many have been looking for. For four years, researchers followed 1,500 Australians with opioid prescriptions for non-cancer pain. They found that participants who consumed cannabis reportedly experienced more pain, anxiety, and difficulty coping than those who did not.
Researchers believe that most of the cannabis was consumed through smoking. Further research is needed to see if other administration methods, such as transdermal absorption, vaporized inhalation, or capsule swallowing could be more (or less) effective.
This study comes at an interesting time. Though it took place before medicinal marijuana was legalized in Australia (Legalization occurred in early 2016), it occurred over the backdrop rapidly spreading international legalization—especially for medicinal purposes. Recently, there has even been much talk among policymakers and physicians about using medicinal marijuana as a replacement for opioid painkillers. They wonder if cannabis might curb the dangerous, growing addiction to opioids that so plague the States, replacing one drug with another safer alternative. So far, the evidence doesn’t support that cannabis can live up to its pain-killing expectations.
The study was funded by the National Health and Medical Research Council, and the researchers found participants by handing out questionnaires at pharmacies concerning the patients’ pain, impairment, physical and mental health, and cannabis use. They recruited the patients who stated that they have been in pain for ten years and have been prescribed opioid painkillers for four. During every assessment intervention over the four years that the study was conducted, participants that consumed cannabis reported more acute and life-impairing pain than those who did not consume it. They also reported a decreased ability to cope with the pain.
These results indicate that cannabis might not be an effective painkiller and may be of limited use in helping patients better cope with the impairing effects of chronic pain. The study further shows no signs that cannabis use will lead participants to reduce or stop taking opioids painkillers. Interestingly enough, the participants who consumed cannabis stated, on self-report questionnaires, that cannabis was effective for them, even though their scores, in comparison with other subjects, indicates otherwise.
The researchers hypothesized that other benefits of cannabis, such as improved sleep quality, may have interfered with the participants’ answers. Perhaps they felt increased wellbeing, but not necessarily decreased pain—which is what they were looking for. Clearly, disentangling one effect of cannabis from another is a messy business. The next step for researchers is to conduct a stronger clinical trial. They’re thinking about following this one up with a double-blind study that controls for expectancy effects and better randomizes its sample. Once this study is conducted, there will be better evidence to inform the ongoing debate over the benefits of cannabis.