Research on pain relief from use of medical cannabis poses myriad challenges. Veteran researchers discuss 2 new studies based on a deep well of user data.
Pain relief is one of the most common reasons for cannabis use cited by medical cannabis users. Supporting evidence, however, is in short supply and limited by effects of study design including type of product used, administration route, dose, and other factors.
Drs Carrie Cuttler and Rebecca Craft from the Department of Psychology at Washington State University, both experienced cannabis researchers, tapped a unique well of medical cannabis user data for 2 recent studies on the acute and long-term effects of inhaled cannabis on headache and migraine and on the acute effects on muscle, joint and nerve pain. Using data from thousands (headache/migraine) and tens of thousands (musculoskeletal/nerve pain) of cannabis use sessions recorded in a medical cannabis app, Cuttler, Craft, and colleagues analyzed whether cannabis use decreased pain and whether factors such as gender, type of cannabis, THC, CBD or dose contribute to changes in pain ratings.
In this video the authors discuss the unique study design and the overall findings from both studies, including the differences in pain attenuation for different types of pain based on sex, smoking vs vaping, and other factors.
For other videos in this interview series:
The following transcript has been edited lightly for clarity.
Patient Care Online. I'm Grace Halsey, Senior Editor of Patient Care Online. And our clinical focus for the month of February is on pain and pain management in primary care. And I've asked our 2 guests today to talk with Patient Care about their recent research on the effects of inhaled cannabis on headache and migraine pain and also muscle joint and nerve pain. Dr Carrie Cuttler and Dr Rebecca Craft are both professors in the Department of Psychology at Washington State University, where they each head a research lab currently studying the impact of cannabis use on a wide range of domains. Welcome to you both.
I'd like to start with Dr Cuttler. Can you just tell us a bit about the research going on in your lab? What you're focused on right now?
Cuttler: Yeah, research in my health and cognition lab focuses on examining the acute and chronic effects of cannabis on mental health, cognition, stress, and here we'll see a little bit of physical health as well. So, we've recently published studies examining the acute effects of cannabis on symptoms of obsessive-compulsive disorder, symptoms of posttraumatic stress disorder and presently we're doing a series of studies examining acute and chronic effects of cannabis on cognition and symptoms of attention deficit hyperactivity disorder.
PCO: As I said, a wide range. And Dr Craft What are you working on in your lab right now?
Craft: So, my lab studies everything in rodents. We work with male and female rats, and my focus over many years has been comparing the pain-relieving effects of drugs in males and females. So, we've done a lot of studies with opioids and cannabinoids a little bit with NSAIDs, and just really trying to determine, are there sex differences in the potency or efficacy of the different major classes of analgesics? And if so, why is that? Is there's some interaction on the drug with hormones in either sex or changes over the estrus cycle, or something like that? So, everything in rodents—it was very exciting to start collaborating with Dr Cuttler, because it was a chance for me to get involved in some research on humans for the first time.
PCO: That was one of my questions, you know, the labs seemed very suited to collaboration. I wondered if you had ever worked before, work together before?
Cuttler: No, we hadn't. This was our first two collaborations, I guess. And they went very well. So I'm hoping to collaborate with Dr Craft again.
PCO: This is why we need to go back into our offices, we need our water cooler conversations. You know, we can't always connect in Zoomland.
Dr Cuttler, why don't you describe the two studies that you two have collaborated on? And particularly the source of your data and how that sets these studies apart from some of the other or a good deal of the research that's been done on cannabis for pain?
Cuttler: So of course, one of the most common reasons that medical cannabis users give for using cannabis is to manage pain, and they do often report that it's effective for this purpose. Now, prior studies have really focused on rodent models like D Craft and then there's of course been lab studies and clinical trials with humans that really kind of contradict that and indicate that cannabinoids might have quite limited effectiveness for ameliorating pain. But a lot of these studies, were very, like I said, controlled lab studies. So, they're using rodent models instead of humans or they're using oral administration instead of inhaled which is more common, or they're using isolated or synthetic cannabinoids, rather than looking at whole plant cannabis. And so few studies had really looked at inhaled whole plant cannabis and its perceived effects on managing pain or reducing pain.
So, we conducted these two studies in a bit of a novel way. What we did was we actually got anonymous archival data from this medical cannabis app called Strainprint™. So again, Strainprint is a medical cannabis app that allows patients to rate the severity of their symptoms immediately before and then shortly after using cannabis. So, by getting the back data from this app, we were able to examine changes in pain severity ratings from immediately before to after inhaling cannabis on a very large scale.
Specifically, for the first study, we analyzed data from over 12 000 cannabis use sessions for treating headache, over 7000 In cannabis use sessions for treating migraine that spanned a period of 6 months. For the second study, we actually analyzed data from over 57 000 cannabis use sessions for treating muscle pain, over 56 000 cannabis use sessions for joint pain, and over 17 000 sessions for nerve pain. And these ones spanned a period of 34 months, making them some of the biggest studies of their kind. And the results really revealed roughly 50% reductions in pain from before to after. So, it's about 47% reduction in headache ratings, 50% reduction in migraine ratings and joint pain ratings; we saw a 49% reduction in self-reported muscle pain ratings. And then finally, nerve pain seemed to be the toughest and that one showed a 42% reduction in ratings from before to after cannabis use. So again, collectively suggesting about a 50% reduction in these pain severity ratings.
PCO: Were there any factors that had any predictive ability for efficacy against the pain?
Cuttler: Yeah, we did examine what factors might help to predict or account for the self-reported reductions in pain severity. We looked at things like gender, time, dose of cannabis used, THC and CBD concentrations in cannabis used. And we found that time, gender, and type of cannabis used predicted reductions in headache. Specifically, we found that men reported larger reductions in headache after using cannabis than did women. We found that cannabis concentrates were associated with larger reductions in headache than cannabis flower. And we also found that later cannabis use sessions were associated with smaller reductions in headaches severity ratings, and that suggests some tolerance to the effects of cannabis on headache might develop over time, that it's becoming less effective as people continue to use it to manage their headaches. Similarly, we found men reported larger reductions in muscle, joint, and nerve pain after cannabis use than did women; we found that vaping was associated with larger reductions in nerve pain, sorry, joint pain than with smoking—so, vaping associated with larger reductions in joint pain than smoking, and lower doses were associated with larger reductions in nerve pain, which was maybe a bit surprising to me. And then we found that later cannabis use sessions again, were associated with smaller reductions in nerve pain, again, indicating some tolerance might be developing to the acute effects of cannabis on nerve pain as well as headache.
Find additional information on Strainrprint.