Summary: Cancer patients who use cannabis to address their symptoms have less pain, sleep better, and after a few weeks of sustained use, appear to think more clearly.
This study is among the first to assess how cannabis bought over the counter at dispensaries affects cancer symptoms or chemotherapy side effects, and sheds light on the wide variety of products cancer patients use now that marijuana is legal in many states.
The findings suggest that while some forms and dosages of cannabis for pain relief may impair thinking short-term, the treatment might improve cognition in the long run by reducing pain.
A small study suggests that cancer patients who use cannabis have less pain, improved sleep and clearer thinking after a few weeks of sustained use.
This study is one of the first to investigate the effects of over-the-counter cannabis bought from dispensaries on cancer symptoms or chemotherapy side effects.
The study’s authors suggest that more research is needed to determine the benefits of cannabis on cognitive function in the long run.
Source: University of Colorado
Angela Bryan had been studying cancer prevention for years and had just started studying cannabis use among cancer patients when, in 2017, her personal and professional lives collided in a way she’d never imagined: She was diagnosed with breast cancer.
Hesitant to take opioids for post-surgical pain, she asked her doctors what they thought about her using the herb medicinally.
“They were so supportive of what I wanted to do, but they had no idea what to tell me,” said Bryan, a professor of psychology and neuroscience at CU Boulder. “There was just no data.”
Fast forward six years, and a small but groundbreaking study helps to fill that gap, showing that cancer patients who use cannabis to address their symptoms have less pain, sleep better and experience another, unexpected, benefit:
After a few weeks of sustained use, they seem to think more clearly.
When you’re in a lot of pain, it’s hard to think,” said Bryan, the study’s senior author. “We found that when patients’ pain levels came down after using cannabis for a while, their cognition got better.”
The study, published in the journal Exploration in Medicine, is among the first to assess how cannabis bought over the counter at dispensaries— rather than government-supplied or synthetic varieties—impacts cancer symptoms or chemotherapy side effects.
It also sheds light on the wide variety of products cancer patients use now that marijuana is legal in most states.
Bringing the lab to the patients
Surveys suggest that as many as 40% of U.S. cancer patients use cannabis, yet only a third of doctors feel comfortable advising them about it.
Studying it is complicated, because federal law prohibits university researchers from possessing or distributing cannabis for research unless it’s government-issued or of pharmaceutical grade.
As a result, most studies have looked only at prescription products like nabilone or dronabinol (typically prescribed for nausea) or government cannabis strains that tend to be less potent and lack the variety of over-the-counter offerings.
For the study, Bryan collaborated with oncologists Dr. Ross Camidge and Dr. Daniel Bowles at the CU Anschutz Medical Campus to observe 25 cancer patients who used cannabis over two weeks.
After a baseline appointment in which their pain levels, sleep patterns and cognition were assessed, they were asked to purchase the edible product of their choosing from a dispensary. Choices were surprisingly varied, spanning 18 brands, including chocolates, gummies, tinctures, pills, and baked goods, and contained varying ratios of THC and CBD at a wide range of potencies.
“This tells us that people are open to trying whatever they think might be useful, but there’s just not much data out there to guide them on what works best for what,” said Bryan.
To study acute impacts, researchers drove a “mobile laboratory” (a Dodge Sprinter van sometimes referred to as the “cannavan”) to each patient’s home one day. Participants underwent physical and cognitive assessments in the van, then re-tested in the van after using cannabis in their homes.
After two weeks of sustained use at the frequency of their choice, they also had a follow-up exam.
Within an hour, the study found, cannabis eased patient’s pain significantly while also impairing their cognition and making them feel “high” (the higher the THC content, the higher they felt).
But longer term, a different pattern emerged: After two weeks of sustained use, patients reported improvements in pain, sleep quality and cognitive function. Some objective measures of cognitive function, including reaction times, also improved.
“We thought we might see some problems with cognitive function,” said Bryan, noting that both cannabis and chemotherapy have been previously associated with impaired thinking. “But people actually felt like they were thinking more clearly. It was a surprise.”
The more people’s pain subsided, the more their cognition seemed to improve.
Notably, those who ingested more CBD, a known anti-inflammatory, reported bigger improvements in both pain intensity and sleep quality.
While larger, controlled studies are needed before drawing conclusions, the authors say the findings raise an intriguing possibility: While some forms and dosages of cannabis for pain relief may impair thinking short-term, the treatment might improve cognition in the long run by reducing pain.
“We know oncologists and patients are concerned about the possible negative impact of cancer treatment on cognitive function, so the potential, indirect role of cannabis use on improving subjective cognitive function should be studied further,” said first author Gregory Giordano, a professional research assistant in the Department of Psychology and Neuroscience.
After surgery and chemotherapy, Bryan did turn to cannabis-infused edibles, creating her own custom regimen of more potent THC-heavy products when pain was intense and she could sacrifice some mental sharpness, and milder, CBD-heavy products to keep the pain manageable.
She was not pain-free, but she didn’t take a single opiate during her treatment.
“I was extremely lucky because I had some knowledge about this. Most patients don’t,” she said. “Either they don’t know it’s an option or they’ve got well-meaning but potentially under-informed budtenders advising them.”
She hopes her team’s research, and more studies to come, will enable doctors and patients to make better-informed decisions.
Cannabis use in cancer patients: acute and sustained associations with pain, cognition, and quality of life
Given the myriad of negative sequalae associated with cancer and its treatment, the palliative use of cannabis by cancer patients is increasingly of special interest. This research sought to explore associations of acute and sustained use of legal market edible cannabis products on pain, cognition, and quality of life in a group of cancer patients.
In this observational study, cancer patients completed a baseline appointment, a two-week ad libitum cannabis use period, and an acute administration appointment that included assessments before cannabis use, one-hour post-use, and two-hour post-use. Participants completed self-report questionnaires related to the primary outcomes and the Stroop task as a measure of objective cognitive function.
Twenty-five participants [mean (standard deviation, SD) age = 54.3 years (15.6); 13 females (52.0%)] completed all study appointments and were included in the analysis. Sustained cannabis use was associated with improvements in pain intensity, pain interference, sleep quality, subjective cognitive function, and reaction times in the Stroop task, but no change in general quality of life was observed. High levels of cannabidiol (CBD) use during the two-week ad libitum use period was associated with steeper improvements in pain intensity and sleep quality. Participants reported improvements in pain intensity and increased feelings of subjective high after acute use. High levels of Δ9-tetrahydrocannabinol (THC) use during the acute administration appointment was associated with steeper increases in feelings of subjective high. Improvements in pain were associated with improvements in subjective cognitive function.
This observational study is among the first of its kind to examine associations between legal market, palliative cannabis use, and subjective and objective outcomes among cancer patients. These early findings concerning pain intensity, sleep quality, and cognitive function can help to inform future, fully powered studies of this important topic (ClinicalTrials.gov identifier: NCT03617692).