- A new study measured the quality of life of more than 3,100 patients who were treated with various forms of medical cannabis, including THC, CBD, and products that combine the two.
- Most of the participants in the study reported using cannabis for chronic non-cancer pain while a smaller number used the drug for cancer pain, insomnia, and anxiety.
- In general, most patients reported improvements in quality of life in all areas, however, some of the changes either returned to baseline over the course of the study or were not clinically important.
Many people with cancer-related pain, chronic pain, or other health conditions turn to medical cannabis to relieve their symptoms.
Now recent research has found that cannabis products may also improve their overall quality of life.
This can happen even without changes in pain levels, said Dr. Wei Du, co-director of Drexel University’s Medical Cannabis Research Center in Philadelphia.
For example, when asked about their pain level, patients may say, “My pain is high, but I still manage to go to work and enjoy time with my family.”
Other times, their pain level may be low, but they can have difficulty functioning in their daily life due to their illness.
The authors of a recent study in the journal
Du said that given how patients’ symptoms may not be an accurate reflection of their overall functioning, patient-reported outcomes such as quality of life can be useful in understanding how medical cannabis benefits people.
In the study, researchers measured health-related quality of life in more than 3,100 Australian patients who were treated with medical cannabis at a network of specialist medical clinics between 2018 and 2022.
The average age of patients at the first study visit was 56 years, over half were female, and around one-third were employed.
Chronic non-cancer pain was the most common reason for using medical cannabis, as reported by over two-thirds of patients. Smaller numbers of patients used medical cannabis for cancer pain, insomnia, and anxiety.
In addition, the most common medications at the first visit were opioid and non-opioid pain medications, the latter used by around half of patients. Some people also reported using antidepressants, benzodiazepines, or other medications.
The researchers did not report on medication usage at the end of the study, so it’s not known if treatment with medical cannabis helped patients reduce their use of other medications.
By the end of the study period, 80% of monthly cannabis prescriptions were for products that were dominant in CBD, with most of these taken orally as oils or capsules. The rest of the products were either dominant in THC or contained a balance of THC and CBD.
“A very small proportion of patients used inhaled forms [of medical cannabis],” said Jason Busse, DC, Ph.D., a professor of anesthesia and associate director of the Michael G. DeGroote Centre for Medicinal Cannabis Research at McMaster University in Hamilton, Ontario, Canada.
“This is comforting in a sense,” he said, “because when you’re using an oil-filled capsule, you’re not going to take on any of the potential pulmonary harms seen with inhaling cannabis.
Medical cannabis comes in many forms, including dried flower, oils, and edibles, with varying potencies, as well as different levels of delta-9-tetrahydrocannabinol (THC), cannabidiol (CBD), and other compounds.
In the United States, enrollment in medical cannabis programs increased 4.5-fold between 2016 and 2020. Some people may also be managing their symptoms with cannabis obtained through the legal recreational market.
Some earlier research has focused on how well medical cannabis reduces specific symptoms such as
Throughout the study, patients answered a survey that assessed their quality of life in a number of areas, including general health, pain, physical functioning, mental health, social functioning, and energy levels.
Patients had follow-up visits about every 45 days, with 15 total visits during the study period. On average, though, patients attended only five or six visits.
Busse pointed out that although this study was more about changes in quality of life than a reduction in symptoms, one aspect of the survey specifically addressed bodily pain.
After starting medical cannabis, patients reported improvements in quality of life in all areas. In one area, physical functioning, patient scores initially increased, but then returned to baseline by the end of the study period.
The changes for each area ranged from 6 to 18 points on a scale of 0 to 100. A 10-point change or larger would be a “clinically important difference,” the researchers wrote.
Busse explained that while some aspects of quality of life changed by more than 10 points, others did not, and overall the changes were not very large.
However, “chronic pain, which is what most of these patients have, is quite challenging to manage,” he said. “We don’t have a lot of great cures. Instead, what we have are a lot of different treatment options that work a little bit for some people.”
In line with this, throughout the study, patient scores remained lower than the average quality of life scores for the general public, the results showed.
The study was funded by Emyria, the parent company of Emerald Clinics, which runs the clinics where patients obtained medical cannabis. The author responsible for the statistical analysis of the data is an employee of Emyria.
Researchers also collected information about negative side effects experienced by patients. Most were either mild or moderate, with around 3% severe.
The most common side effects were sedation, sleepiness, dry mouth, lethargy, tiredness, and dizziness.
The low risk of severe side effects may be due to more patients choosing CBD-dominant products, said Busse, because “a lot of the side effects of medical cannabis products are associated with the THC component.”
Overall, the results “give us some reassurance that use of these products — at least for half a year or sometimes longer — did not appear to be particularly problematic, in terms of harms,” he said.
Du, a professor, and chair of the Department of Psychiatry at Drexel University College of Medicine, said one limitation of the study is that it is retrospective, meaning researchers collected patient data after the fact.
This type of study makes it harder for researchers to control for other factors that can affect patient outcomes, in this case, quality of life.
In contrast, Du is running a prospective study that will look at the impact of medical cannabis on the quality of life of people living with HIV, neuropathic pain, or post-traumatic stress disorder (PTSD).
In this study, Du and his colleagues will recruit patients and then follow them over time.
Another limitation of the new study is that it is observational, with no comparison group of people who didn’t use medical cannabis. Patients were also aware that they were receiving medical cannabis, which can affect the outcomes.
In addition, researchers reported changes in average scores, which are based on a range of patient responses, with some patients responding well to medical cannabis and others less so.
Busse said it might have been easier to interpret the results if the authors had reported the percentage of patients who saw an improvement of 10 points or more.
However, the study is consistent with similar observational studies, he said, but the effects are larger than what you see with randomized controlled trials.
Still, the results suggest “that patients are continuing to use [medical cannabis products] because the benefits exceed the harms,” he added.