Cannabidiol may be effective in halving the severity of symptoms and impairment caused by chronic anxiety, a pilot study by Orygen, Australia's center of excellence in youth mental health, has shown.
The Cannabidiol Youth Anxiety Pilot Study found that young people with treatment-resistant anxiety had an average 42.6% reduction in anxiety severity and impairment following 12 weeks' treatment with cannabidiol—a non-intoxicating component of the Cannabis sativa plant, which is often referred to as CBD.
Orygen's Professor Paul Amminger, who led the study, said this level of improvement was remarkable.
"The young people had fewer panic attacks and could do things which they were previously unable to do like leave the house, go to school, participate in social situations, eat at restaurants, take public transport or attend appointments by themselves," Professor Amminger said.
"That's an amazing change in the group which has had treatment-resistant, long-standing severe to very severe anxiety."
The reduction in symptoms was observed on two different scales: a clinician-rated scale (the Hamilton Anxiety Rating, 50.7%) and a self-rated scale (the Overall Anxiety Severity and Impairment Scale, 42.6%), which involved participants filling in a questionnaire on symptoms such as panic attacks, situational anxieties, worries, and flashbacks.
Study co-investigator and Orygen Executive Director, Professor Patrick McGorry said the findings held promise for a significant number of young people, with Australian Bureau of Statistics data released on 22 July showing anxiety was the most common form of mental ill-health in young people, affecting nearly a third (31.5%) of those aged 16–24—almost double the rate of the general population.
"We're seeing more and more young people experiencing anxiety—it's the fasting growing form of mental ill-health in young people and we urgently need innovation in treatment. Cannabidiol is a promising treatment option which appears safe and effective. We need further research to confirm this and explore its value," Professor McGorry said.
The pilot study involved 31 participants aged 12–25 who were recruited from Orygen's primary care services. The participants had a diagnosed anxiety disorder and had failed to show significant improvement in anxiety severity following at least five cognitive behavioral therapy (CBT) sessions.
"The problem with current frontline treatments for anxiety—CBT and selective serotonin reuptake inhibitor (SSRI) antidepressant drugs—is that they only work in about half of the people who try them," Professor Amminger said.
"Anxiety disorders are very common so that leaves a large number of young people untreated, struggling with symptoms and developing secondary conditions, for instance depression and substance use disorders."
Orygen started exploring cannabidiol as an anxiety treatment after it was found to be effective in reducing anxiety in adults.
In Australia, cannabidiol has been approved by the Therapeutic Goods Administration as a treatment for children with rare forms of epilepsy (Dravet syndrome and Lennox Gastaut syndrome). Cannabidiol has been approved for clinical trials as a treatment for children in Australia with Tourette Syndrome, Fragile X syndrome, autism spectrum disorder, and intellectual disability.
"It's important to stress that cannabidiol does not induce any significant side effects or lead to the emergence of any neurological or psychiatric manifestations," Professor Amminger said.
"Cannabidiol is non-intoxicating and doesn't contain tetrahydrocannabinol (THC) so it doesn't cause alterations in thinking and perception, it doesn't make you 'high' and it's not addictive. In fact, cannabidiol has been used to treat addictive behaviors in other research trials and can reduced some of the adverse and intoxicating effects of THC."
Pilot study participants' starting dose was one 200mg capsule of cannabidiol per day, which was increased to 400mg after one week. Those who did not show significant improvement in anxiety symptoms had their dosage increased at 200mg increments up to 800mg per day. All participants were offered biweekly CBT for 12 weeks (five sessions).
"Our pilot study found that cannabidiol not only helped to reduce anxiety symptoms but it was also very well tolerated—the most common side-effects were mild sedation and mild fatigue but that was at the time when doses were increased and usually went away after a couple of days," Professor Amminger said.
"We did not see side-effects like suicidal thoughts, irritability or sleep problems, which are not uncommon in people taking SSRIs."
Although the findings are promising, further research is required.
"An open-label pilot study is limited by its design. To see a treatment effect in the treatment-resistant group is encouraging, but it could still be a placebo effect. The next step is a randomized controlled trial, which is the gold standard to test a new intervention. Such a trial needs to be done in a much larger group—around 200 to 250 young people—to enable us to say with some certainty that there is, or is not, real treatment benefits and effects," Professor Amminger said.