Medical Cannabis Needs Better Research
/By Roger Chriss, PNN Columnist
Much of the uncertainty and reluctance about using medical cannabis stems from a lack of high-quality research. Instead of randomized controlled trials, surveys and data-mining are commonly seen, leaving clinicians and policymakers with little to work with.
That is the basis for the American Medical Association’s concerns about states legalizing medical cannabis.
“Scientifically valid and well-controlled clinical trials conducted under federal investigational new drug applications are necessary to assess the safety and effectiveness of all new drugs, including potential cannabis products for medical use,” the AMA declared in a policy statement.
Good research would help reduce such concerns. Unfortunately, a lot of recent research involves poor methodology and problematic funding, weakening potentially useful results.
For example, a recent study published in the journal Cureus found that cannabis was a “useful adjunct and substitute for prescription opioids” for chronic pain patients and had the added benefit of improving their physical function and quality of life.
To conduct the study, researchers surveyed 550 patients being treated at three licensed medical cannabis clinics in the northeastern United States, using an anonymous online survey consisting of 11 questions about medication use, pain levels and side effects.
This is very problematic. A convenience sample is a simple method for quickly grabbing data. Its downsides are that it isn't random and is subject to a lot of selection bias. And anonymous surveys are unreliable. As a 2018 Australian study showed, claims of prescription opioid use by people using medical cannabis are often very inaccurate.
Similarly, an observational study at 21 medical clinics in Canada found that the “high rate of cannabis use for chronic pain and the subsequent reductions in opioid use suggest that cannabis may play a harm reduction role in the opioid overdose crisis.”
But the study was sponsored by Tilray, a Canadian cannabis firm that has provided cannabis for clinical trials and is involved in the adult recreational-use market in Canada. Drug studies sponsored by industry need to be viewed with caution, since such studies are known to produce results favorable to the sponsoring organization.
In general, studies that collect data through convenience samples or anonymously via online surveys or apps are not reliable. And studies funded by industry may be biased.
What Happened to Sue Sisley’s Study?
Good studies do get done. However, their results are not always published.
In 2019 Sue Sisley, a psychiatrist at the Scottsdale Research Institute in Phoenix, finished a study on cannabis for post-traumatic stress disorder (PTSD) that took ten years to complete, promising that “the full results of the study, including all the data, will be publicly released."
But Sisley’s research still hasn’t been published. Last year she admitted the study findings may have been compromised by the poor quality of cannabis that the DEA allows for research.
“Most scientists end up with this mishmash of different strains (including stem sticks, leaves, etc.) — all of it seems to get thrown into a grinder in an overzealous effort to standardize the study drug batches for clinical trials," Sisley said.
Research results need to be published even if they are not positive. There is a tendency to promote positive results and hide negative findings. Publication takes a lot of time and effort, and negative results may impede the flow of research dollars.
But if the benefits and risks of medical cannabis are to be better understood, we need all the results. And researchers should get full credit for their work, even if the results aren’t what advocates or enthusiasts were hoping for.
Medical cannabis needs more high-quality research. Surveys of people recruited from a medical cannabis dispensary cannot be generalized to the population at large, and studies sponsored by industry must be treated with caution. Improving medical cannabis research will go a long way toward helping people use medical cannabis safely and effectively.
Roger Chriss suffers from Ehlers Danlos syndrome and is a proud member of the Ehlers-Danlos Society. Roger is a technical consultant in Washington state, where he specializes in mathematics and research.
