Dr. David Pompei, PharmD, MS
According to pain researchers, “no human experience is more compelling than that of intense pain.” Many people use cannabis and CBD as a natural way to manage their mild day-to-day pain.
It could be a young woman who finds that a few puffs from a high THC vape pen at the onset of her migraines dramatically decreases her symptoms; or a hard-charging dad who uses CBD capsules to soothe his inflamed joints after a weekend of hiking with his grown children; or a cancer survivor with lingering nerve pain from chemotherapy who traded prescription opiates for a few puffs from a joint on the recommendation of her doctor.
Cannabis has been used to soothe pain for at least 5000 years. Around 2000 years ago, the Shennong Ben Cao Jing, an ancient Chinese encyclopedia on medicine and agriculture, listed cannabis as a treatment for over 100 ailments including pain, inflammation, epilepsy and wound healing.
By the 19th century, cannabis was regarded as an effective pain reliever and hypnotic. Over one hundred medical publications in the United States and Europe discussed the plant’s therapeutic benefits. However, with the development of synthetic opiates and NSAIDs, “the prevalence of cannabis as a medicine and its necessity as an analgesic…began to decline.”
While cannabis might not be a mainstream pain reliever anymore, many medical marijuana patients use cannabis to manage their mild day-to-day pain. According to research conducted by Leafwell, chronic pain was the most common qualifying health condition reported by medical marijuana patients in 2020.
Many medical marijuana patients feel that weed is highly effective for pain relief. For example, a 2019 survey of medical cannabis patients found that 65% of patients reported taking cannabis to relieve pain, and of that group, 80% reported that cannabis was “very or extremely helpful” for managing their pain.
A separate study conducted on 2987 people reporting their cannabis use and symptom relief found that cannabis benefitted numerous pain conditions including non-specified pain, headaches, back, muscle or joint pain, and gastrointestinal pain. These researchers noted that whole cannabis flower was associated with greater pain relief than any other type of product, and that higher THC levels were “the strongest predictors of analgesia.” Interestingly, CBD levels “were not associated with pain relief.”
A study published in October of 2020 found similar results. The researchers analyzed 131,582 cannabis sessions and participants’ self-reported symptom relief and found that “inhaled cannabis reduces self-reported pain severity by ~42-49%.” For all pain types they studied (muscle pain, joint pain and nerve pain), “severity ratings decreased significantly after cannabis use.” Interestingly, the researchers found no statistically significant relationship between THC or CBD content and pain relief, but they did observe that vaped cannabis was associated with larger reductions in joint pain than smoked cannabis. They also indicated there was evidence of tolerance, in that patients had to increase their cannabis dose over time to maintain the same level of pain relief.
Clearly people feel that cannabis helps them manage their pain, but these data come from self-reported studies rather than clinical studies. What do clinical studies indicate about cannabis and pain?
The scientific literature holds seemingly contradictory findings. For example, despite the survey results above, many clinical studies indicate that cannabinoids only have weak analgesic properties.
A 2018 editorial published in the Journal of Applied Laboratory Medicine (JALM) states, “systematic reviews in acute pain are unequivocal in pointing out the lack of effectiveness of cannabinoids.”
A 2018 review of pain and cannabis published in the journal Pharmacotherapy discusses the surprisingly lackluster results of clinical trials: “oral pharmaceutical grade cannabinoids show conflicting results…In addition to their limited efficacy to treat pain, tolerability seems to be a major limitation for clinical use. The number of patients who stop treatment with oromucosal cannabinoids due to drug-related adverse events is larger than the number of patients observed when using the cannabis plant.”
Despite evidence that whole plant cannabis is effective in managing mild pain from exercise or daily life, a 2020 review published in the Journal of Pain Research concluded, “Use of herbal cannabis…is not suitable to manage pain or other medical conditions.” How is it possible that people feel cannabis is highly effective at managing their pain, but clinical trials indicate that cannabinoids and cannabis are weak or ineffective analgesics?
Part of the issue is that federal prohibition on cannabis has caused significant problems for researchers, as Jointly discussed in Do Concentrates Get You Higher than Flower?
For example, legal restrictions make it impossible to study real-life cannabis products in a controlled laboratory setting. Furthermore, decades of prohibition have created a situation where there simply aren’t many scientifically rigorous studies on cannabis and pain. As a result, “the current clinical debate continues to be driven, in large part, by variable analyses and perspectives of the same extant clinical trials.” However, federal restrictions are only a piece of the puzzle.
You might have noticed that the 2018 editorial in JALM distinguishes between “cannabinoids” and “medical cannabis.” Many of the studies that found minimal benefit for pain used synthetic cannabinoids. Modern medicine and pharmacology follow a standard path of developing “safer and more efficacious drugs than plants themselves.” However, there is evidence that isolated cannabinoids and current synthetic cannabinoids may have less therapeutic benefit than the whole plant.
For example, the 2018 review published in Pharmacotherapy states, “surprisingly, and as an unforeseen paradox to modern pharmacy…oral pharmaceutical grade cannabinoids show conflicting results in patients with chronic pain.” The authors of the review note that the evidence indicates that “oral cannabinoids are inferior when compared to…the cannabis plant.” The editorial in JALM concedes, “it may be presumptuous to conclude that the major clinical effects of cannabis are derived solely from THC and cannabidiol (CBD). What becomes lost in the rhetoric…[is] the putative analgesic effects of terpenes and flavonoids.”
Beyond terpenes and flavonoids, there may be lesser known cannabinoids in the whole cannabis plant that contribute to its pain-relieving effects. For example, a September 2020 article published in the medical journal Comprehensive Clinical Medicine notes there are “hundreds of cannabinoid compounds…in the cannabis plant that variably activate CB1 and CB2 receptors.”
Part of the reason why clinical studies have produced mixed results may be that these studies largely use isolated or synthetic cannabinoids, which seem to have less therapeutic benefit for pain relief than the whole plant.
In line with this idea, the surveys and self-reported studies indicate that cannabis flower is more effective than other types of products for relieving pain. Supporting this notion, the National Academy of Sciences, Engineering, and Medicine found “substantial evidence that inhaled cannabis is effective for the treatment of chronic pain in adults.”
There are three main pain systems: nociceptive pain, neuropathic pain, and central pain.
When your tissue is inflamed or injured, special pain detecting neurons called nociceptors transmit this information “via nociceptive pathways in the spinal cord to the brain.”
Your brain interprets these signals and creates the subjective experience of pain.
In nociceptive pain, the nervous system is functioning normally and noxious stimuli like disease, inflammation or injury activate the nociceptors, “leading to organized responses that defend the tissue under threat and aid in its repair.”
Neuropathic pain is caused by “damage to sensory or spinal nerves, which send inaccurate pain messages to higher centers.” Neuropathic pain is characterized by spontaneous pain, allodynia (pain from normally innocuous stimuli), and hyperalgesia (excessive pain from something that would normally be mildly painful).
Central pain can be nociceptive or neuropathic, but is caused by “dysfunction that specifically affects the central nervous system, which includes the brain, brainstem and spinal cord.” Fibromyalgia is the classic example of central pain. Basically, the central nervous system amplifies the pain signal, making the pain impossible to ignore.
Pain researchers discovered that in some circumstances, acute pain can lead to “hyperexcitability” of the nociceptors, essentially lowering the threshold needed to activate these pain neurons. This plasticity is unique: “unlike other sensory systems, nociceptive systems can sometimes undergo very long lasting, even permanent, enhancement of function following sufficiently intense activation.” This process leads to “amplification of incoming [pain] signals,” and is a substantial part of neuropathic and chronic pain conditions.
During World War II, H.K. Beecher, a physician serving with the U.S. Army, observed that nearly three quarters of severely wounded soldiers were “alert, responsive and not in shock…reported no to moderate pain [and] did not want pain relief medication.” Beecher’s observations were the first indication that the body has natural mechanisms of modulating pain, which we now know can either diminish or magnify pain.
Pain modulation refers to the process by which “the body alters a pain signal as it is transmitted along the pain pathway.” This innate pain modulation is an important part of how cannabis helps people manage pain. While endorphins (the body’s endogenous opioids) are known to play a role in pain modulation, preclinical studies have revealed that the endocannabinoid system plays an important role as well.
For example, when researchers injected rats with naloxone, an opioid receptor antagonist that blocks the effects of opioids, alongside a synthetic cannabinoid that exerts similar effects to THC, they observed effects “analogous to the effect of morphine, but these effects were not blocked by naloxone, indicating that these effects are mediated specifically through cannabinoid receptors.”
The pain-relieving effects of cannabis and opiates like morphine are due to these compounds interacting with your body’s natural pain modulation pathways: the endocannabinoid system and the endogenous opioid system.
As Kevin Hill, MD et al. write in their 2017 clinical review of cannabis and pain, “understanding the function of endogenous cannabinoids helps explain the efficacy of exogenous cannabinoids…in treating pain.”
The endocannabinoid system is made up of the CB1 (cannabinoid receptor 1) and CB2 receptors and the endogenous cannabinoids (anandamide and 2-AG) that bind to them. The CB1 receptors are found in the brain, nervous system, peripheral organs and tissue, while the CB2 receptors are found primarily on immune cells, although they are also found on bone, spleen and liver cells.
Research has shown that the endocannabinoid system “acts independently of the opioid pathway to control pain signaling, immune activation, and inflammation.” While the endocannabinoid and opioid pain pathways act independently, scientists have found that CB1 receptors are “found in high concentrations in areas of the brain that modulate nociceptive processing, with a similar distribution to opioid receptors.”
Additionally, we know that “the analgesic effect of THC is, at least in part, mediated through…opioid receptors.” Research has revealed that endogenous opioids and endocannabinoids “are present in primary sensory neurons, offering the possibility to relieve, or at least reduce, the noxious inputs at their initial stage.” That means that after an injury the body produces endocannabinoids that reduce inflammation and pain signaling at the site of injury, which reduces pain.
A 2018 article published in the University of Western Ontario Medical Journal states, “activating ECS (endocannabinoid) receptors…contribute[s] to the body’s natural ability to relieve pain and reduce inflammation.” Either endocannabinoids or exogenous cannabinoids from cannabis can activate the endocannabinoid receptors and exert this analgesic effect.
Both cannabinoids and opioids relieve pain through a mechanism that “blocks the release of pain-propagating neurotransmitters in the brain and spinal cord.”
As Kevin Hill, MD et al. write in their clinical review, due to the complex ways that the endocannabinoid system modulates pain, “the biologically hypothesized rationale for cannabinoid administration is whole-body exposure to exogenous cannabinoids to turn on pain inhibition.”
We know that endocannabinoids (which interact with the same receptors as exogenous cannabinoids) can reduce inflammation and pain signaling at the site of injury, both of which reduce pain. We also know that activating CB1 receptors in the spine “inhibits neurotransmitter release and pain transmission,” and that activating CB1 receptors at the supraspinal level “inhibits nociceptive transmission.”
Essentially, activating the cannabinoid receptors “by endogenous or extraneously administered cannabinoids” inhibits pain signals and neurotransmitter release locally, at the spinal level and at the supraspinal level. There is also evidence that when the endocannabinoid system is activated, it downregulates neuronal hyperexcitability.
There are a variety of mechanisms by which CBD can help people manage pain. While CBD doesn’t bind to cannabinoid receptors, it does increase the levels of anandamide, the endocannabinoid that binds to CB1 receptors (like THC). As established, activation of the CB1 receptors plays an important role in pain modulation.
Many factors can affect how pain is experienced: your emotional state, your degree of anxiety, whether you are distracted or focused on the pain, your expectations about the pain, etc.
Experimental studies on cannabis and pain indicate that cannabis increases the threshold at which participants feel pain, and decreases the unpleasantness of pain, but does not reduce the intensity of pain.
A separate study drew the conclusion that cannabis affected only one of three subjective measures of pain: bothersomeness. The other two measures were pain intensity and a McGill Pain Questionnaire. This finding is critically important to understand why cannabis is such an effective tool for managing pain.
While cannabis may not decrease the intensity of pain in the same way opioids do, it makes pain more tolerable—and also does not seem to increase sensitivity to pain in the same way opioids do. Cannabis has the ability to affect “the emotional component of pain” by boosting mood, reducing symptoms of anxiety or depression, and “offering some degree of dissociation from physical symptoms.”
According to the biopsychosocial model, pain is not simply a biological process, but one that involves a person’s psychology and larger social network. If pain is less bothersome, it may be psychologically easier to tolerate, and have less of a negative impact on well-being. Please note this information is for educational purposes only, and any changes to your pain management strategy should be discussed with your doctor. Curious if cannabis or CBD can help you manage pain?
Use Jointly, a brand-new cannabis wellness app, to learn if cannabis and CBD can help you achieve your wellness goals. For example, if your goal is pain management, you can use Jointly to track your cannabis use and symptom relief in real time. Jointly is a free tool that allows you to track and record your CBD and cannabis consumption, including the dose, time of use, composition of the cannabis product and various other factors that can influence your experience.
As you track your cannabis consumption on Jointly, you will learn about the factors that can impact your cannabis experience and how to eliminate side effects. You will also gain important insights from the Jointly community. For example, in general Jointly users find better results with managing pain when consuming topicals, edibles or flower compared to tinctures or vape pens. To learn why we might be seeing these data, head over to Jointly Product Type Report Volume 1.
Perhaps you will discover that you find the best results with managing pain when you vape flower after you have worked out, and with some food in your stomach. You need to track and record your cannabis consumption on Jointly to learn that about yourself. As you use the app, Jointly will suggest new routines and better products.
When you use Jointly, you are actually rating how well a product helped you achieve your wellness goal. Over time, your average ratings should go up as you optimize how you consume cannabis and CBD. Use the Monitor Your Progress feature to make sure your results are improving over time.
Looking for products to help you manage your pain? Brands and manufacturers have designed a vast range of legal cannabis and CBD products for this exact purpose: CBD-infused roll-on topicals; high THC Indica vape pens; flower strains purported to relieve pain.
Jointly is a cannabis discovery app that makes it easy to find and match with the best cannabis and CBD products for your goals. Your matches are calculated from the real product ratings and experiences of hundreds of thousands of people using the Jointly app.
With Jointly, match with top-rated products, and build lists of your favorites to save, share, and bring to your local dispensary to help guide your shopping experience.
Jointly also helps you track your cannabis experiences through reflections that help you understand what’s working, and what’s not. In fact, the quality of your diet, how much you slept, who you’re with, and the time of day are just some of the factors that can impact your experiences.