Flower is being increasingly prescribed for anxiety despite a lack of clinical evidence supporting its use, according to a new study led by the Lambert Initiative for Cannabinoid Therapeutics.

Using data from the Therapeutic Goods Administration’s Special Access Scheme, including almost 250,000 approved scripts, the researchers found anxiety was among the top three reasons for a medicinal cannabis prescription at 16%, along with pain (61%) and sleep disorders (7%).

Senior author of the study Dr Elizabeth Cairns

While flower-based products containing THC has been prescribed for the condition, particularly to males aged 31 and under, senior author Dr Elizabeth Cairns said the current evidence base is limited to a few studies investigating CBD-dominant products, rather than those containing THC.

“Historically, the effects of THC have been described as anxiety-inducing, although this may depend on dose size and other factors,” she added.

Medicinal cannabis has been prescribed for more than 140 conditions since legalisation in 2016, according to the study. Prior to 2020, people aged 45 to 52 were the largest group of patients, whereas after 2020, 20 to 31-year-olds were the predominant group.

The findings come after an analysis by Cannabiz found patients are getting younger, ‘maler’ and more anxious, though their preference for flower has not yet been enough to displace oil as the most frequently dispensed product.

The top three reasons for prescriptions did not surprise study co-author and cannabis prescriber, associate professor Vicki Kotsirilos.

She said: “Pain, anxiety and sleep issues are often interconnected – chronic pain can also cause mental health and sleep issues.”

Although she prescribes medicinal cannabis for pain, Kotsirilos insisted it should only be as a last resort, after more evidence-based behavioural and drug therapies such as counselling, exercise and deep breathing have failed or are of limited clinical benefit. 

In a press release, Lambert said: “The evidence of effectiveness for medicinal cannabis in the treatment of pain is controversial, at least in Australia, where the Faculty of Pain Medicine suggests not to prescribe [it] for this purpose.

Associate professor Vicki Kotsirilos

It added: “Very few studies have been done examining cannabis for the treatment of sleep disorders.”

The researchers found that medicinal cannabis prescriptions have increased significantly since 2020, with more than 85% of the total being issued since January that year. They were unable to confirm whether the rise was pandemic related.

Queensland was responsible for 51% of prescriptions nationally.

Lambert said the size of the dataset allowed the team to find prescribing patterns in small, but significant, populations that otherwise might have been overlooked.

“Apart from the link between anxiety and flower products, we found other interesting associations, for example, prescriptions of topical CBD for convulsions,” Dr Cairns said.

“This usage has not been extensively explored.”

The authors noted, however, that the data doesn’t include patient outcomes.

Dr Cairns added: “Unfortunately, we just don’t know if these treatments were effective for these patients, but this data highlights where we can focus our attention next — to do focused studies and/or clinical trials.”

“There is a clear, unmet need for effective drug treatments across a variety of conditions that may be being helped with medicinal cannabis.

“For example, it could be worth conducting high-quality clinical trials on the use of flower products for anxiety, and that is certainly something that the Lambert Initiative and its collaborators may look to do in future.”

The findings are published in Frontiers in Pharmacology.

Prior to launching Cannabiz, Martin was co-founder and CEO of Asia-Pac’s leading B2B media and marketing information brand Mumbrella, overseeing its sale to Diversified Communications in 2017. A journalist...