By Emily Ledger
Research into the potential of cannabis and its derivatives as a medical treatment has been on the rise in recent years as demand for alternative therapies pushes to the forefront. We commonly hear about the use of cannabis-based products for the treatment of conditions like epilepsy and chronic pain – but could medical cannabis be useful in treating chronic migraine?
Cannabinoids, such as CBD and THC, have been found to interact with receptors in our bodies – known as endocannabinoid receptors (CB1 and CB2). These receptors are part of a wider network known as the endocannabinoid system, which also includes neurons called endocannabinoids.
This system has been implicated in a number of physiological and cognitive functions, including sleep and mood regulation and pain signalling. Indeed, a role for the ECS has also been proposed in migraine models.
A recent review aimed to build on this finding and determine how a medical cannabis preparation could aid in the treatment of chronic migraine.
What is Chronic Migraine?
While many people may suffer from infrequent or even one-off migraines, acute migraine refers to a much more specific pattern of impairment. This condition is characterised by experiencing at least 15 ‘headache days’ per month, with at least eight days of having headaches with migraine features, for more than three months.
Chronic migraine has been linked to significantly lower quality of life, with patients often forced to take a large number of medications, such as painkillers and other prescription drugs.
Other symptoms of chronic migraine can include increased sensitivity to light, sounds or smells; nausea and vomiting; visual disturbances; and dizziness and vertigo.
It is still not fully understood what causes chronic migraine, however, sufferers often demonstrate changes in the brain, and factors such as anxiety, depression, and other pain conditions may exacerbate symptoms. According to the Migraine Trust, around 2.5 out of every 100 people with episodic migraine will develop chronic migraine every year.
How could medical cannabis help?
Researchers aimed to assess the effects of orally-administrated cannabinoid preparations in chronic migraine patients. A total of 32 patients who had not responded to first- and second-line recommended preventative treatments (due to inefficacy or adverse events) or when such treatment options were contraindicated, were recruited between 1st January 2019 and 31st December 2019.
Cannabis preparations were prescribed as an off-label (blinded) additional treatment for chronic migraine. The researchers compared monthly migraine days (MMD) at baseline (prior to medical cannabis initiation) and again at 3 months and 6 months after the start of treatment.
Pain intensity using the numeric rating scale, the number of acute medication consumption (AC) and the number of days per month in which patients used at least one medication (NDM) were also measured and 3 and 6 months.
Did medical cannabis treatment help?
The researchers observed a number of interesting results following both 3 months and 6 months of cannabinoid treatment. While the total number of monthly migraine days (MMD) did not improve in comparison to baseline, pain intensity scores were seen to decrease significantly at both follow-ups.
The AC and NDM also followed a downward trend, with patients taking fewer medications on fewer days after both 3 months and 6 months of treatment. In addition, the number of patients with nausea and/or vomiting attacks significantly decreased after 6 months of cannabinoid treatment.
While a significant proportion of participating patients (n=14; 43.75%) experienced at least one adverse event, the majority were mild and did not result in the discontinuation of treatment. However, two patients (6.25%) experienced moderate vertigo and ceased treatments – with side effects being resolved following suspension.
The bottom line
This study demonstrated that oral cannabinoid preparations are able to improve symptoms, including pain and nausea/vomiting, and quality of life associated with chronic migraine. The authors note that these results were observed in a severely impaired population, with patients experiencing almost daily migraine attacks, who were using more than one preventive medication per day, had a long history of illness and had not responded to many preventive treatments in the past.
The researchers also note that the population sample displayed a high rate of psychiatric and rheumatological comorbidities that may reduce the effectiveness of preventive medications and may also have affected the effectiveness of oral cannabinoid preparations.
A lack of significant reduction in Monthly Migraine Days in this study may be linked to the severe impairment of patients at baseline. However, these results reflect the ECS central action as a regulator of pain perception as demonstrated by a significant reduction in pain intensity scores.
Overall, these findings suggest a potential role for oral cannabinoid preparations in patients with chronic migraine who are forced to resort to a high use of pain-relieving medications. The authors of this study recommend further investigation – namely, randomised placebo-controlled studies with large samples – in order to better understand the role of the endocannabinoid system in chronic migraine.