By Pat Anson, PNN Editor

The use of medical cannabis was associated with “significant improvements” in physical and mental health in a large survey of Australian adults suffering from chronic pain and other health problems.

Over 3,100 people participated in the survey. Chronic non-cancer pain was the most common condition reported (68.6%), followed by cancer pain (6%), insomnia (4.8%) and anxiety (4.2%).  

Australia has relatively stringent rules for medical cannabis. Patients have to exhaust all other forms of treatment and consult with a physician, who reviews their medical history and suitability for cannabis before writing a prescription.

Most of the prescriptions for survey participants were for cannabis products taken orally, such as oils and capsules, with only a small number for dried cannabis flower. About 80% of the cannabis products were rich in cannabidiol (CBD), with the rest dominant in tetrahydrocannabinol (THC) or a balanced mix of CBD and THC.

Patients were asked to rate their wellness and quality of life in eight categories on a scale of 0-100, including general health, body pain, physical functioning, physical limitations, mental health, emotional limitations, social functioning and vitality. The surveys were conducted at the start of the study and then every 45 days after cannabis therapy was initiated, with a total of 15 follow up surveys.   

The study findings, recently published in JAMA Network Open, showed sustained improvement in all eight wellness categories after participants started taking cannabis, with body pain improving an average of 10 to 15 points on the 100-point scale. Researchers also found “pronounced and statistically significant improvements” in mental, social and emotional health.

“This study suggests a favorable association between medical cannabis treatment and quality of life among patients with a diverse range of conditions. However, clinical evidence for cannabinoid efficacy remains limited, and further high-quality trials are required,” wrote lead author Thomas Arkell, PhD, a psychopharmacologist at the Swinburne University of Technology in Melbourne.

Adverse events such as sleepiness and dry mouth were relatively common during cannabis therapy, but were usually mild or moderate.

Before starting cannabis therapy, patients were taking an average of nearly five medications a day, the most common being simple analgesics (54%), opioids (48%), antidepressants (45%), benzodiazepines (34%) and gabapentinoids (22%). The study did not examine if medication use declined once participants started taking cannabis.  

“While we cannot exclude the possibility that adverse events may have been caused in whole or part by the disease state and concomitant medications, the relatively high incidence of adverse events still affirms the need for caution with THC prescribing and careful identification of patients with contraindications,” Arkell wrote.

Medical cannabis was legalized in Australia in 2016. Since then, over 332,000 Australians have been given cannabis prescriptions, mostly for chronic pain (55%), anxiety (23%) and sleep disorders (6%).

Pain management experts in Australia have long taken a dim view of cannabis. In 2021, the Australian and New Zealand College of Anaesthetists released new guidance urging doctors not to prescribe medical cannabis for chronic non-cancer pain because of a lack of good quality research.