Exploring the benefits of medical cannabis for different types of pain

Pain and pain-related diseases are the leading cause of disability and disease among the global population. Pain is defined as an unpleasant sensory or emotional experience associated with actual or potential tissue damage. In simple terms, pain is our body’s way of indicating a potential danger, prompting us to take action to avoid damage. However, for many individuals, the experience of pain can go far beyond an essential reaction for survival.

What are the different types of pain?

Pain can be categorised in a number of ways, the most simple being to determine whether it is chronic pain (persists for more than three months), acute pain (starts suddenly and resolves when the cause is treated/healed), or episodic pain (pain that occurs occasionally at irregular intervals). Pain may also be categorised as:

• Musculoskeletal pain: Occurs when there is damage to the bones, joints, ligaments, tendons, or muscles through injury or damage due to certain medical conditions.

• Nociceptive pain: Occurs due to potential or actual tissue damage either due to injury (cuts, burns, etc) or when a medical condition causes damage to the body.

• Inflammatory pain: Occurs when tissue is damaged or becomes infected, causing the activation of the body’s inflammatory response.

• Neuropathic pain: Also known as nerve pain or neuralgia, occurs when the nervous system is damaged or malfunctions.

Medical cannabis for pain conditions

Cannabis has been used in the treatment of pain for thousands of years. More recently, a growing number of clinical studies have aimed to establish a mechanism for cannabis’ pain-relieving potential, with a major focus on the endocannabinoid system (ECS). 

The ECS is a receptor system that plays a vital role in a range of cognitive and physiological functions, including pain signalling. Some evidence indicates that cannabinoids such as CBD and THC may help regulate pain signalling via their interactions with cannabinoid receptors throughout the body.

Arthritis

Arthritis refers to over 100 conditions that affect the joints causing pain and inflammation. The mechanisms of these conditions can vary; for example, rheumatoid and psoriatic arthritis occur when the immune system mistakenly attacks healthy tissue, while osteoarthritis is a degenerative disease that causes the cartilage around joints to break down over time. Some types of arthritis (including rheumatoid and psoriatic arthritis) are also associated with inflammatory pain.

There is no cure for arthritis; treatments instead focus on managing the symptoms, including pain. However, many patients struggle to achieve satisfactory pain relief using conventional therapies which often leads to them seeking alternative treatments, including medical cannabis.

Medical cannabis can be prescribed for arthritis in the UK. In fact, current data indicates that 1 in 5 medical cannabis patients in the UK are using cannabis to manage arthritis. While clinical research in this area remains underdeveloped, some evidence suggests that cannabidiol (CBD) may help improve pain, physical function, and sleep quality in patients with arthritis. Real-world evidence also indicates that medical cannabis treatment is associated with improvements in pain-related outcomes.

Fibromyalgia

Fibromyalgia is a complex chronic pain condition that causes pain and tenderness all over the body, in addition to other symptoms such as sleep problems and fatigue, and comorbid conditions including anxiety and depression.

It is not fully understood what causes fibromyalgia, but it is more common in individuals who also have other conditions that cause pain (including some types of arthritis, lupus, and ankylosing spondylitis) and other diseases. Brain imaging studies indicate that altered signalling in neural pathways may cause increased pain sensitivity in individuals with fibromyalgia.

There is no cure for fibromyalgia and diagnosis can be difficult and take a long time. Treatments for the condition focus on pain management and the reduction of other symptoms; however, these are often insufficient at providing satisfactory relief.

There is also growing evidence to support the potential of medical cannabis for fibromyalgia. A 2023 review of current research found evidence that cannabinoid-based therapies were associated with short-term pain reduction in patients with fibromyalgia. Medical cannabis may also help to improve quality of life - a significant consideration for this population of patients.

Ehlers-Danlos syndrome (EDS)

Ehlers-Danlos syndrome (EDS) is a group of 13 rare genetic disorders that affect the connective tissues in the body. The condition can range in severity from relatively mild to potentially life-threatening. Symptoms can include an increased range of joint motion, stretchy skin, and fragility in the skin, bones, blood vessels, and some organs. Some types of EDS can also cause chronic pain. 

Treatments for EDS-associated pain include using supports for joints that are unstable to minimise pain and reduce the risk of injury. Patients may also be prescribed medications such as muscle relaxants, tricyclic antidepressants, and selective serotonin reuptake inhibitors, as well as physical therapy.

Research into medical cannabis for EDS remains limited; however, there is some indication that cannabis-based medicines may be useful for managing EDS-related pain. This was supported by the findings of a 2021 case study in which a patient with EDS experienced significantly reduced pain following the initiation of cannabinoid therapy.

Migraines

Migraines feel like very bad headaches that are commonly characterised by throbbing pain on one side of the head. They can be experienced with or without other symptoms, including vision problems, dizziness, nausea, and mood changes. The cause of migraines is unknown, but they have certain triggers. Some hypotheses define migraine pain as a unique neuropathic pain disorder.

Treatments for migraines can include over-the-counter painkillers, prescribed medications such as triptans, and lifestyle changes. However, these treatments are not always effective and can leave patients seeking alternative therapies.

While clinical research in this area is limited, a number of studies have indicated that medical cannabis may be effective at reducing the length and frequency of migraines. Moreover, current studies indicate that medical cannabis treatment for migraines was not associated with any severe side effects.

Complex regional pain syndrome (CRPS)

Complex regional pain syndrome (CRPS) is a chronic pain condition that is most often triggered by an injury. It is associated with long-lasting severe and debilitating pain. There are two main subtypes of CRPS: CRPS-1 - the most common - occurs after illness or injury but is not associated with any specific nerve damage; CRPS-2 is associated with damage to a specific nerve.

In CRPS, the pain experienced is disproportionate to the degree of injury and persists beyond the normal expected time for tissue healing. It is unclear why CRPS develops in some people. While treatment methods such as physical therapy, psychotherapy, and pain medications may be helpful to ease some symptoms, many patients struggle to achieve adequate pain relief.

Several randomised controlled trials that assessed cannabinoids for pain relief have included patients with CRPS. In one study of patients with neuropathic pain, 22 of the 38 participants were diagnosed with CRPS. Overall, patients reported significant pain relief following the inhalation of THC flower. 

Sciatica

Sciatica occurs when the sciatic nerve - the longest nerve in the body which runs from the lower back down to the heels of the feet - becomes irritated or compressed. It can be caused by a slipped disc, spinal stenosis, spondylolisthesis or other types of injury. 

This disruption to the sciatic nerve causes neuropathic pain that can be felt in the lower back, buttocks, down the back of the legs and into the feet. Other symptoms of sciatica include tingling and numbness in the skin. Treatment of sciatica can include physiotherapy, painkillers (oral or intravenous), and surgery. 

Several studies have focused on the potential of medical cannabis for managing neuropathic pain. A 2018 review of randomised controlled trials found that multiple studies have demonstrated that medical cannabis was able to achieve similar efficacy and tolerability to conventional pharmacotherapies in various etiologies of neuropathic pain.

Endometriosis

Endometriosis is a condition in which tissue similar to the uterus lining grows outside of the uterus. This triggers the body’s inflammatory response, leading to inflammation and scar tissue forming in the pelvic region and, less commonly, other areas of the body. Endometriosis is associated with severe pain in the pelvis and can make it harder for those with the condition to get pregnant. 

Patients with endometriosis often experience additional symptoms, including heavy bleeding, fatigue, depression, and anxiety. Treatments for endometriosis can include medications such as non-steroidal anti-inflammatory drugs (NSAIDs) and analgesics, hormonal medicines or devices, and surgery.

Studies have demonstrated the vital role of the ECS in potentially preventing the development of endometriosis, indicating that cannabinoid receptors may be a novel target for effective therapies. While clinical evidence is still lacking, medical cannabis treatment for endometriosis may be considered when other approaches have failed.

Final thoughts

A growing body of research is examining the potential of medical cannabis for chronic pain conditions. Today, cannabis-based medicines can be considered for the treatment of a wide variety of conditions, including those mentioned in this article. As Dr David Tang, medical cannabis prescriber and Releaf's Clinical Director, notes: 

“Many conditions that lead to chronic pain often respond poorly to conventional pharmaceutical medications. More and more is being understood about how the endocannabinoid system interacts with the more well-known pain pathways to work synergistically with these conventional medications. 

“Chronic pain comes with a variety of associated symptoms such as poor sleep, fatigue, brain fog and reduced appetite – all of which treatment with medical cannabis could improve.”

Since 2018, specialist doctors in the UK have been able to prescribe cannabis-based medicines for patients who have been unable to achieve satisfactory relief with conventional treatments. Learn more about getting a medical cannabis prescription and discover if an alternative approach could help you to better control your symptoms.