The most common self-reported reason to use medical cannabis is for pain management. As well as being a commonly used pain relief tool in modern times, cannabis was also historically used for this purpose. As we progress in the field of cannabis science, we are learning more and more about why cannabis is such an effective pain management tool and the reasons people might choose it over traditional pain-relief drugs such as opioids.
There is a growing body of evidence for how and why cannabis works for pain management, and the topic becomes especially interesting when we look at conditions such as fibromyalgia and the role of the endocannabinoid system. It is generally believed that the effects of cannabis on the human endocannabinoid system are the reason it causes pain relief, but it might even be deeper than this. A chronic endocannabinoid deficiency might be at the root cause of painful conditions such as fibromyalgia, and using cannabis may restore balance in endocannabinoid systems that are dysfunctioning.
In this article, we explore the case for the use cannabis in pain management, how it works, and which cannabinoids play a role in causing pain relief for users.
Understanding the science behind cannabis and pain relief
Firstly, it’s important to identify that in the world of medicine, “pain” is an umbrella term for a set of subjective symptoms felt by a person rather than a blanket definition. Pain is highly subjective and can be caused by so many different factors that pain is considered to be an element of virtually every single disease. Because of this, it’s extremely difficult to identify a chemical or biological cause of pain – rather, it is a symptom of something else. In this way, pain relief very rarely targets the cause of the disease. It simply gives a patient a better quality of life while they investigate and ultimately treat the underlying cause.
To understand the science behind the use of cannabis for pain relief, it’s important to have a basic idea of how the human endocannabinoid system works. The human endocannabinoid system is something like a reverse nervous system. They work in the reverse order to neurotransmitters in that they are produced on demand in postsynaptic terminals rather than stored in presynaptic vesicles. For this reason, they typically are an “off switch” for many neural pathways.
Endogenous cannabinoids produced by the endocannabinoid system perform the following actions:
- They decrease the release of neurotransmitters
- They activate inhibitory pain pathways (with neurotransmitters activating excitatory pain pathways)
- They reduce postsynaptic activity
In a sense, this activity is very similar to the way that opioids produce pain relieving properties, but opioids do not target the endocannabinoid system. Rather, they target neurotransmitters. Some scientists like Ethan Russo believe that a condition called Clinical Endocannabinoid Deficiency Syndrome (CECD) actually underlie painful conditions such as fibromyalgia and migraines, and that cannabis’ activation of the endocannabinoid system restores the balance and therefore relieves pain.
While drugs such as opioids inhibit the action of neurotransmitters that cause pain responses, cannabinoids reduce pain by activating CB1 and CB2 receptors, activating the endocannabinoid system, and inadvertently switching off the neuronal pathways to pain. It is the same action but in reverse.
The research behind cannabis’ efficacy for pain relief
It is arguably the most abundantly researched area of medical cannabis – its use for pain relief. With that being said, studies have shown that certain kinds of pain are treated more effectively with cannabis, while with other types of pain cannabis only has a modest analgesic effect.
For example, in a study consisting of patients undergoing abdominal hysterectomy, patients were studied for pain relief of 5mg THC versus placebo. No significant analgesic effect was recorded. However, in other studies conducted specifically on those experiencing chronic pain, cannabis was shown to be effective in reducing pain scores.
The general scientific consensus is that cannabis is more effective in instances of neuropathic pain, and especially chronic pain, than it is in instances of acute, physiological pain. This means that if a person breaks their leg, cannabis is unlikely to be the best choice of analgesic, but if a person experiences nerve pain such as carpal tunnel or fibromyalgia, cannabis may be a highly effective form of pain management.
In this systematic review, non-cancer patients with chronic neuropathic pain conditions such as fibromyalgia, arthritis, and mixed chronic pain experienced a significant reduction in overall pain after using cannabis. This ties in closely with Ethan Russo’s theory of CECD and why cannabis is effective in only some forms of highly treatment resistant chronic pain conditions.
CBD or THC – which cannabinoid works best for pain?
There is ongoing debate about which cannabinoid is most effective in reducing pain – THC or CBD? The truth is that both compounds use different mechanisms of action to produce pain relief, meaning that a certain cannabinoid might be better in certain circumstances. On top of this, CBD is non-psychoactive, making it a preferred option for those who are sensitive to the effects of THC or who want to avoid the psychoactive effects.
There are two primary cannabinoid receptors in the human body – CB1 and CB2. The CB1 receptor is primarily located in the central and peripheral nervous system, such as in the brain and spinal cord. The CB2 receptor, on the other hand, is primarily found in the immune and hematological systems. Interestingly, CBD doesn’t have a strong affinity for either CB1 or CB2 receptors, and produces pain-relieving effects through other mechanisms, such as at the serotonin receptor, 5HT1A and other ion channels. THC, on the other hand, has a strong binding affinity to CB1 and CB2 receptors, and its use reduces pain by interfering with the neural pathways that cause a person to feel pain.
This difference in how cannabinoids move through the human body is likely the explanation why for some people, CBD seems to work better for pain management while for others, THC is the preferred option. There is no scientific consensus on whether THC, THC-CBD, or straight CBD is better for pain relief, and data until now are highly inconsistent.
The clinical significance of cannabis as a pain relief drug
We are still in the early stages of understanding how and why cannabis works as a pain relief drug and who it might work best for. Often when a field of study is deep into understanding the pharmacokinetics of a drug and its mechanism of action, we overlook other very important factors of clinical significance. The reduction of opioid use among marijuana users is one of those factors.
Irrespective of scientific data, there is growing anecdotal evidence that cannabis works as a pain relief drug for so many people around the world. In a 2016 study, researchers found that there was a 64% reduction in opioid use among patients who used medical marijuana for pain relief. Because of the harms associated with ongoing and excessive opioid use, this point is of extremely high clinical significance. The apparent ability for marijuana use to reduce the need for potentially harmful drugs such as opioids can be considered a pertinent reason to continue to study cannabis and its effects on pain, as well as ways it can be better targeted.
Choosing the right cannabis products for pain management
The world is still adapting to the reintroduction of cannabis as a pain relief drug, and many doctors still don’t know which cannabis products a person should be using. Rather, people find themselves attending cannabis clinics whose practitioners have specialized knowledge, and can then be guided towards cannabis products suitable for their pain relief needs.
As we mentioned earlier in this article, some people may opt for CBD-rich products in order to avoid the psychoactive effects of THC. Others may choose a more balanced product at the expense of the “stoned” effect, or even because the “stoned” effect contributes to their pain relief. Some users conscientiously avoid using smoked or inhaled products, as this can be counterproductive when using cannabis for medicinal purposes.
It’s obvious that there are many ways a person can use cannabis, and a huge variety of products that a person can access for pain management. Ultimately, choosing the right product relies heavily on preference of consumption method and psychoactivity. Beyond this, it may be a matter of trial and error to find a strain or product that is most effective. Some people choose to use indica products at night as this may not just reduce pain, but also induce sleep and reduce pain-associated insomnia. They may use sativa products during the day to achieve pain relief without the drowsiness or couch-lock effect.
Using cannabis for pain management should be an ongoing process with a specialized doctor or practitioner who can guide you towards the best product and how best to use it. This will look different for every person based on their preferences and the kind of pain they are experiencing.
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