Review Finds THC More Effective Than CBD for Chronic Pain
/By Pat Anson
An updated systematic review found that cannabis products with relatively high levels of THC (tetrahydrocannabinol) may provide small improvements in chronic pain; while those containing high levels of CBD (cannabidiol) and little or no THC had minimal effect on pain.
Researchers at the Pacific Northwest Evidence-based Practice Center at Oregon Health & Science University reviewed 25 short-term cannabis studies involving over 2,300 patients with chronic pain. Their findings are published in the Annals of Internal Medicine.
CBD-based gummies, tablets, oils and other products have long been marketed for various health issues, but researchers say they demonstrated almost no improvement in managing pain.
“This may be surprising to people,” said lead author Roger Chou, MD, in a press release. “Conventional wisdom was that CBD was promising because it doesn’t have euphoric effects like THC and it was thought to have medicinal properties. But, at least in our analysis, it didn’t have an effect on pain.”
Chou, who was lead author of the controversial 2016 CDC opioid guideline and its 2022 update, said the small improvement in pain was on the order of a half point to a point on the zero-to-10 pain scale. While providing modest pain relief, THC-based products also had a higher risk of side effects, such as dizziness, sedation and nausea.
There are several caveats to the review which make it unhelpful, at best, in determining whether THC or CBD are effective pain relievers.
One, many of the clinical trials were deemed to be biased or of low quality. They mostly involved patients with chronic neuropathic pain, which means they don’t necessarily apply to patients with other types of pain.
Second, most of the studies involved pharmaceutical-grade cannabis-based medicines, such as dronabinol and nabilone, which are approved for nausea, vomiting and as an appetite stimulant. None of them are approved for pain relief.
Third, those pharmaceutical medicines are based on synthetic THC, not plant-derived THC or CBD. So basically, the researchers studied products that most cannabis consumers don’t use
“This raises critical questions about generalizability: Can findings from standardized formulations inform real-world use of diverse, cannabis-derived, state-regulated products?” asks Ziva Cooper, PhD, from the UCLA Center for Cannabis and Cannabinoids, in an editorial also published in the Annals of Internal Medicine.
Copper says the review demonstrates the need for better evidence and less reliance on clinical trials. The inclusion of observational studies and patient reviews of products obtained in dispensaries would better capture real-time evidence of current cannabis use and outcomes.
“There are opportunities for novel approaches to understand cannabis-related health effects. Rigorous randomized controlled trials (RCTs) are the gold standard for determining the safety and efficacy of cannabis and cannabinoids for therapeutic end points,” Cooper wrote.
“Yet, these studies are resource-intensive, challenging due to federal regulations, and slow to adapt to a rapidly evolving marketplace and patient behavior. Expanding the scope of study designs to consider complementary strategies is urgently needed.”
Chou says the wide variety of cannabis products on the market makes drawing conclusions about their effectiveness difficult.
“It’s complicated because cannabis products are complicated,” he said. “It’s not like taking a standardized dose of ibuprofen, for example. Cannabis is derived from a plant and has multiple chemicals in addition to THC and CBD that may have additional properties depending on where it’s grown, how it’s cultivated and ultimately prepared for sale.”
Better cannabis research is one of the reasons the Trump Administration is moving to complete the process of reclassifying cannabis from a Schedule I controlled substance to a Schedule III drug with accepted medical uses.
Because cannabis has long been illegal under federal law, it has stifled research into its health benefits, leaving patients and doctors in the dark on its potential uses. This review does nothing to shine a light on the issue.
