Angela Bryan has been studying cancer prevention for years and had just begun studying cannabis use among cancer patients when, in 2017, her personal and professional lives collided in a way she could never have imagined: she was diagnosed with breast cancer. Recent research into the influence of cannabis is groundbreaking.
Hesitant to use opioids for postoperative pain, she asked her doctors what they thought about her using the herb medicinally. "They were so positive about what I wanted to do, but they had no idea what to tell me," says Bryan, a professor of psychology and neuroscience at CU Boulder. “There was just no data.”
Pioneering study of cannabis
Now, six years later, a small but groundbreaking study seems to help fill that gap. Not only does it appear that cancer patients who cannabis to address their symptoms, have less pain, but also sleep better and experience another unexpected benefit: after a few weeks of long-term 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 lead author. “We found that when patients' pain decreased after using cannabis for a while, their cognition improved.” The study, published in the journal Exploration in Medicine, is one of the first to assess how over-the-counter cannabis — rather than government-supplied or synthetic varieties — affects cancer symptoms or side effects of chemotherapy. It also sheds light on the wide variety of products used by cancer patients now that marijuana is legal in most states.
Research on cannabis strains
Surveys suggest that as many as 40% of cancer patients in the US use cannabis, but only a third of doctors feel comfortable advising them about it. Studying it is complicated, as federal law prohibits university researchers from possessing or distributing cannabis for research unless it is government-issued or pharmaceutical-grade. As a result, most studies have looked only at prescription products such as nabilone or dronabinol (usually prescribed for nausea) or government cannabis strains that are typically less potent and lack the variety of over-the-counter products.
For the study, Bryan teamed up with oncologists Dr. Ross Camidge and Dr. Daniel Bowles at the CU Anschutz Medical Campus to observe 25 cancer patients using cannabis for two weeks. After a baseline meeting that assessed their pain level, sleep patterns, and cognition, they were asked to self-purchase an edible of their choice from a pharmacy. The choices were surprisingly varied: chocolates, gummies, tinctures, pills, and pastries. The procts contain a different ratio of THC and CBD. "This tells us that people are open to trying anything they think might be useful, but there just isn't a lot of data to help them determine what works best for what," Bryan said.
To study acute effects, one day researchers drove a “mobile lab to each patient's home. Participants underwent physical and cognitive assessments and were then retested after using cannabis at home. After two weeks of long-term use at the frequency of their choice, they also had a follow-up examination. Within an hour, the study found, cannabis significantly relieved patients' pain, while also affecting their cognition and giving them a "high" depending on THC levels.
Long term effects
Longer term, a different pattern emerged: After two weeks of long-term 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," Bryan said, noting that both cannabis and chemotherapy have previously been linked to impaired thinking. “But people actually felt like they were thinking more clearly. It was a surprise.”
The more people's pain decreased, the more their cognition seemed to improve. In particular, those who took more CBD, a known anti-inflammatory, reported greater improvements in both pain intensity and sleep quality.
While larger, controlled studies are needed before conclusions can be drawn, the authors say the findings open up an intriguing possibility: While some forms and doses of cannabis for pain relief may actually impair thinking in the short term, long-term treatment may improve cognition by reducing pain.
“We know that oncologists and patients are concerned about the potential negative impact of cancer treatment on cognitive function, so the potential, indirect role of cannabis use in improving subjective cognitive function needs further study,” says first author Gregory Giordano, a professional research assistant in the Department of Psychology and Neuroscience.
Source: medicalexpress.com (EN)
