Pain can be a good thing. After all, it warns us of threats to our well-being. But when pain becomes a long-term issue, it can have a significant impact on our quality of life. The approaching legalization of cannabis – better known as marijuana – in Canada has many wondering if it is a good option for pain relief.
Chronic pain is no stranger to many Canadians – nearly 20% of adults live with it on a daily basis (1). Unfortunately, the odds of suffering from chronic pain increase with age, and women are more likely to be affected than men.
Neuropathic pain – which arises from damage to the nerves – accounts for about one in five cases of chronic pain (2). Common culprits of this type of pain include accidents, injuries, or surgery, and symptoms or complications of an illness such as diabetes (3). People will often experience sensations like numbness, tingling, jabbing, freezing, or burning (4).
Neuropathic pain is also notoriously difficult to treat (2). Medications that are normally prescribed for other types of pain (e.g., non-steroidal anti-inflammatories or opioids) are often ineffective (3). Studies suggest that cannabis may help relieve chronic neuropathic pain (5). But does the evidence stand up to the hype, or are the pain-relieving properties of cannabis all smoke and mirrors?
What the research tells us
Two compounds in cannabis – THC and CBD – are thought to contribute to cannabis’s ability to relieve pain. THC can alter pain perception by reducing anxiety and stress, while CBD combats pain through its anti-inflammatory action. Cannabis-based medications come in several forms and can by inhaled by pipe or cigarette, or can be taken orally by spray or capsule.
A systematic review found that compared to placebo, cannabis-based medications may provide moderate to substantial pain relief, and can reduce pain intensity, sleep problems, and psychological distress (5). Unfortunately, these benefits are often associated with side effects such as sedation, confusion, and psychosis. Similarly, a more recent review found that cannabinoids—substances found in the cannabis plant—can improve sleep quality and pain intensity in people with chronic neuropathic pain. Again, these benefits can come with an increased risk of nausea, dizziness, and daytime sleepiness or drowsiness (6). For some people, these side effects may be severe enough to outweigh cannabis’s pain-relieving benefits.
Overall, the quality of the research around cannabis for neuropathic pain relief is very low to moderate. That is not to say that neuropathic pain sufferers should disregard cannabis as a treatment option – it may work for some, but not for others. The bottom line is that there is currently a lack of high-quality evidence supporting cannabis-based medicines for neuropathic pain relief. More high-quality research is needed to confirm its benefits. New research may be particularly important in older adult populations, and in people with health conditions that predispose them to nerve pain. In the meantime, cannabis may be a useful option for people who fail to get adequate relief from established treatment options (5).