A group of scientists at the University of Sydney has received a $1.7 million grant from NSW Health to explore the potential of using the cannabis-derived compound cannabidiol (CBD) to treat spinal cord injury-induced chronic pain.

CBD is the second most prevalent active ingredient in cannabis (marijuana). Unlike the more famous cannabinoid tetrahydrocannabinol (THC), CBD does not induce a "high" in users.If the forthcoming trial is successful, it will offer gold-standard proof that CBD can alleviate neuropathic pain in patients who undergo spinal cord injury (SCI). The study's findings will also help to educate the general public, bolster patient access, and transform policy change regarding medicinal cannabis products that are enriched with CBD, which may harbor anxiolytic, anti-inflammatory, and neuroprotective properties.Neuropathic pain, a type of pain that occurs due to spinal cord damage, may cause a sensation similar to pins and needles. In many cases, the pain is so intense that it can disrupt daily life. Approximately 70% of SCI patients will endure persistent pain to some extent. One-third of those people experience extreme pain that impacts mood, functioning, and quality of life."Current treatment options for neuropathic pain are limited and often come with significant side effects that make the condition worse, highlighting a need for new treatment options," said the study's lead investigator Professor Luke Henderson. Henderson, who works at the University of Sydney's Brain and Mind Centre and the School of Medical Sciences, emphasized the importance of finding new treatment options for patients with spinal cord injury."Anecdotally, some people report that cannabis and its derivatives can improve neuropathic pain. However, no one fully understands how it works to improve pain," said the Director of the Spinal Injuries Unit at the Prince of Wales Hospital, Dr. Sachin Shetty.

Medical Cannabis Use is on the Rise Among Australians

According to recent National Drug Strategy Household Survey research, 2.7% of Australia's population used cannabis for medicinal purposes in 2019. This figure has been inflating rapidly since the plant was made available via prescription when the Australian federal government passed legislation in November 2016,"Doctors are increasingly prescribing cannabis-based products for neuropathic pain. But the lack of clinical studies makes it difficult for doctors to guide patients on the correct dosage for optimal efficacy and safety," said co-investigator of the study, Professor Iain McGregor from the University of Sydney's Lambert Initiative for Cannabinoid Therapeutics. "The lack of intoxicating properties of CBD and its promising effects in animal models of neuropathic pain identifies CBD as a suitable treatment worthy of further investigation."In collaboration with the Lambert Initiative for Cannabinoid Therapeutics - a long-term research program investigating cannabis' medicinal potential - the forthcoming Australian cannabis trial is the first in the world to explore whether or not the non-psychotropic compound cannabidiol (CBD). It will investigate the safety and efficacy of CBD treatments.

The CBD market alone amassed $5.18 billion in global market revenue in 2021."This study will use advanced brain imaging techniques to identify and understand the specific changes that occur in the brain after a spinal cord injury that lead to the development of neuropathic pain," said Ph.D. candidate and study coordinator Ms. Rebecca Robertson, who works at the University of Sydney's School of Medical Sciences. "This study also aims to identify a biomarker that will predict whether an individual will respond to CBD treatment, allowing for a more individualized treatment."Separate Research Highlights Cannabis’ Benefits for Spinal Cord Injury-Induced PainAlthough no cure exists for patients with spinal cord injury (SCI), such as those who experience partial or full paralysis, cannabis has been shown to relieve various associated symptoms, such as mental health, sleep, and post-quality life.

Research suggests that cannabis could reduce opioid use in people with lower back pain and spinal injuries. A study performed at a single-center cannabis medical practice in California demonstrated that cannabis can reduce opioid use in cLBP patients. Of the 180 patients with lower back pain, 61 were active opioid users. Patients who managed back pain with opioids were advised to use medical cannabis. After consuming the plant in pharmaceutical form, researchers monitored changes in morphine equivalents and the number of patients who curbed/stopped opioid intake.

The authors noted that 50.8% of respondents altogether quit opioids. Of the remaining 29 patients, 9 (31%) reduced use, 3 (10%) remained at the same use, and 17 (59%) increased use.On the other hand, one scoping review on the effect of cannabis on pain intensity in patients with spinal cord injury revealed that "the current quality and level of evidence is insufficient to draw reliable conclusions of the efficacy of cannabis upon SCI-related pain intensity." (Pavithra A Thomas et al. J Spinal Cord Med. 2022 Sep) Researchers reviewed information from 252 studies and articles published in electronic databases through February 2020

Australian Cannabis Trial to Commence at World-leading Research Facility

SCI patients chosen to participate in the upcoming Australian cannabis trial will be offered the opportunity to try CBD and a placebo over two separate six-week periods at Neuroscience Research Australia (NeuRA) in Randwick, Sydney. NeuRA is a world-leading facility for brain imaging and spinal cord injury research. The substances will be administered randomly during each treatment period, seeing patients rate their pain and wear a wrist-worn device to measure their sleep.

Before and after each treatment, participants will attend NeuRA to take a brain scan and questionnaires and collect blood."If effective, this trial will provide gold-standard evidence to support the use of CBD for patients with neuropathic pain following spinal cord injury. It can also help to inform and ultimately change policy surrounding the prescription of medicinal cannabis for the treatment of neuropathic pain and improve patient access," said Professor McGregor."Success of this trial would trailblaze future research on the benefits of CBD in other neuropathic pain conditions which, much like neuropathic pain following spinal cord injury, remain undertreated and misunderstood."

Sources:

https://www.sydney.edu.au

https://www.health.nsw.gov.au

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4604171/

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9370304/

https://dataverse.ada.edu.au/dataset.xhtml?persistentId=doi:10.26193/WRHDUL

https://www.sydney.edu.au/medicine-health/schools/school-of-medical-sciences.html

https://pubmed.ncbi.nlm.nih.gov/32923663/

https://pubmed.ncbi.nlm.nih.gov/33465022/

https://redcap.sydney.edu.au/surveys/?s=3PDYK79LCPXLNTRY

Participants must be aged 18 or over and experience neuropathic pain after a diagnosed spinal cord injury. Participants must also be willing to travel to Sydney city on four separate occasions. Limited spots are available. Anyone interested in learning more about the SCAN trial can visit https://bit.ly/SCAN_study. Alternatively, call 0439 804 551 to participate or email [email protected].