Initial results from a study into the effects of medicinal cannabis on the health of people living with chronic illnesses have found that the drug significantly improves health-related quality of life, fatigue, pain, anxiety, and depression. The researchers are analyzing 12-month results to see if the effects last over the longer term.
Living with a chronic illness can considerably reduce quality of life by interfering with physical, mental and social functions. The Quality of Life Evaluation Study (QUEST) is one of the world’s largest longitudinal studies examining the effect of medicinal cannabis on the overall health-related quality of life of patients with chronic health conditions.
The Australian study, led by the University of Sydney, was supported by Little Green Pharma, which provided the medicinal cannabis, and the Health Insurance Fund of Australia (HIF), a not-for-profit private health insurance provider. The researchers are now reporting the three-month interim results of the study.
The researchers enrolled 2,327 participants aged between 18 and 97. Before starting medicinal cannabis treatment, participants completed the EQ-5D-5L health status questionnaire, the European Organization for Research and Treatment of Cancer Quality of Life (QLQ-C30) questionnaire, Patient-Reported Outcomes Measurement Information System (PROMIS) Short Forms in Fatigue and Sleep Disturbance, and the Depression Anxiety Stress Scale (DASS-21). The questionnaires were repeated every two weeks after commencing treatment and every one-to-two months thereafter for up to a year.
Half of the participants (53%) were prescribed medicinal cannabis for more than one health condition, with the majority (68.7%) treated for chronic pain. Other common conditions included insomnia (22.9%), anxiety (21.5%), and mixed anxiety and depression (11%). Participants were prescribed a mix of delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD) in different dosages dissolved in a carrier oil. Doses used in the study reflected real-world clinical practice rather than the large CBD or THC doses typically given in randomized controlled trials.
Results from the first three months of treatment found “very strong evidence of clinically meaningful improvements” in health-related quality of life and fatigue. "Clinically meaningful improvement" refers to findings that have a significant and important impact on a person’s health and/or well-being.
For participants with chronic pain, pain scores improved significantly over time. Those with anxiety or mixed anxiety and depression also showed clinically meaningful improvement, on average moving from moderate-severe anxiety down to mild anxiety. Similarly, participants with depression (including mixed depression and anxiety, recurrent depressive disorder and bipolar disorder), on average, shifted from severe to moderate depression. Interestingly, despite the improvement in fatigue, no statistically significant or clinically meaningful improvement was seen in sleep outcomes.
“The QUEST results show that medicinal cannabis provides statistically, and more importantly, clinically significant improvements in pain levels, fatigue and quality of life for patients,” said Jamie Rickcord, an independent general practitioner involved in the study. “Doctors can have confidence in offering medicinal cannabis as an option to those who qualify for it as [a] result of emerging real-world data provided by initiatives such as QUEST.”
While adverse effects were not measured as part of the study, it’s noted that 30 participants withdrew due to “unwanted side effects.”
The researchers are now analyzing 12-month results to ascertain whether improvements are maintained over the longer term. More research is needed to understand the full effects of medicinal cannabis for treating sleep-related conditions, including looking at formulations, dosing and routes of administration.
The published paper notes that while the University of Sydney received funding from Little Green Pharma to conduct this study, Little Green Pharma played no role in the study design, the collection, analysis, and interpretation of data, and the report's writing. The study was independently investigator-led, and all authors take responsibility for the integrity of the data and the accuracy of the data analysis.
The study was published in the journal PLOS One.
Sources: HIF, Little Green Pharma via Newswise
