Since the rescheduling of cannabis in November 2018, medical preparations of the plant can now be legally prescribed to patients in the UK for a number of indications. These indications include epilepsy, multiple sclerosis, and chronic skin conditions, however, one of the most common reasons for a medical cannabis prescription is for chronic pain conditions.
According to The British Pain Society, chronic pain conditions such as fibromyalgia and arthritis, affect around 43% of the UK population – of which 14.3% of cases would be described as either moderately or severely disabling. Despite this high prevalence rate, there remain few effective treatment options for patients living with chronic pain.
The exact cause of chronic pain is largely unknown with triggers varying from patient to patient. This makes it difficult to effectively treat chronic pain conditions. Currently, the most common treatments focus on the management of associated symptoms and include the prescription of painkillers (mostly opioids) and anti-depressants, behavioural and talking therapies, and exercise regimes.
Medical Cannabis and Chronic Pain
Chronic pain conditions are often associated with lower quality of life due to their impact on factors such as sleep quality, mood, and mobility. In recent years, research has increasingly shown that medical cannabis products may help to alleviate some symptoms of chronic pain and improve quality of life for patients.
Design and Methods of the Study
A recent study aimed to understand how prolonged medical cannabis use can affect pain perception and quality of life scores in patients with chronic non-cancer pain (CNCP). To measure these outcomes, researchers designed a cross-sectional questionnaire-based study which was completed by participants at one-month intervals.
Data was gathered using an existing database of Israeli patients with a pre-existing medical cannabis license for various indications. Each patient had discussed with a relevant physician to decide on the suitable form of administration (either flower for smoking/vaporisation or oral oil preparations) and dosage. A link to the questionnaire was emailed to participants at one-month intervals throughout the six-month period.
This study utilised two validated questionnaires: the EuroQol5 (EQ5D-5L), a validated measure that tracks five domains of quality of life (mobility, self-care, daily activities, pain/discomfort, and anxiety/depression). Sleep quality was also assessed using the Pittsburgh sleep quality index (PSQI) which assesses time of sleep (e.g. 21:00h), sleep latency (minutes), waking time, and sleep duration (hours).
Results of the Study
After the application of exclusion criteria, including the form of medical cannabis used, a total of 429, 150, 98, 71, 77, and 82 responded to the survey at month 1, 2, 3, 4, 5, 6, respectively. Importantly, all study participants (429) reported at month 1.
Changes to Pain Measures
The data collected throughout this study revealed that the least, average, and worst weekly pain intensities did not vary significantly between study follow-ups. However, significant descending usage rates of analgesic medications were reported, from 46% (210) at month 1 to 28% (23) at month 6. This suggests that participating patients were able to achieve similar pain management with a reduction of other analgesic medication such as opioids.
Furthermore, there was no change in the monthly medical cannabis dose, number of cannabis cultivars used (2-3 per patient), or in pain frequency. There was, however, a significant positive improvement in some quality-of-life measures.
Changes to Quality of Life Measures
During the six-month study period, the researchers identified a significant increase in quality of life scores culminating in a difference of 13% (scores = 49% as month 1, increasing to 62% at month 6). These findings indicate that the addition of medical cannabis to ongoing chronic pain treatment can positively affect associated symptoms, improving quality of life.
However, the researchers identified no significant changes during the study period in sleep latency, sleep duration, and time in bed, which may often have an impact on patient’s quality of life scores.
The results indicate that, while pain intensity was not significantly affected throughout the course of the study, a reduction in analgesic medication use was observed. These results support the findings of previous studies suggesting that medical cannabis use can help chronic pain patients to reduce their opioid consumption.
This study also demonstrates that medical cannabis may have a clinically significant effect on quality of life scores in patients with chronic pain. The researchers conclude that these findings “may shed light on the long-term beneficial effects of medical cannabis on chronic non-cancer pain. However, it is also noted that future studies in this area should aim to measure medical cannabis treatment over a prolonged period, taking into consideration patient status prior to treatment.