Is CBD a Remedy for Autism?
Cannabis is one of the oldest domesticated crops. Throughout history, all civilisations have grown different varieties of cannabis for both industrial and medicinal uses.
The cannabis plant contains unique compounds called cannabinoids. Current research has revealed over 60 different cannabinoids so far. THC is the most abundant constituent of the cannabis plant, and the most well known. THC is responsible for causing the marijuana high.
Cannabidiol (CBD) is one of the dozens of compounds found in the cannabis plant. But unlike its more notorious chemical cousin tetrahydrocannabinol or THC – the psychoactive ingredient in marijuana – CBD produces no euphoric “high.”
Cannabidiol (CBD) is not considered a controlled substance in the UK and is therefore 100% legal.
Tetrahydrocannabinol (THC) is the psychoactive chemical responsible for causing the marijuana high and is illegal.
Still, there is emerging evidence and abundant anecdotal reports that suggest CBD can induce profound effects on the brain, spurring a growing market for largely unproven products that tout CBD as a remedy for numerous neurological disorders, from simple stress to epilepsy to post-traumatic stress disorder and drug addictions.
Accumulating evidence suggests that in many cases of autism, there’s a reduction in the brain’s “inhibitory tone” . This suggests that cannabis-based medications, particularly CBD-rich preparations that enhance the brain’s inhibitory signalling, may be a potential autism treatment.
How Cannabidiol (CBD) May Help Autism
The successful Phase III clinical trial demonstrating CBD’s antiepileptic effects in children with treatment-resistant epilepsy was exciting news for epilepsy and medicinal cannabis communities. However, it did not address whether CBD treatment was effective at combating any other aspects of the disorder, like ASD.
Over the last couple of years, my lab has been researching CBD’s ability to treat seizures and autism in our mouse model of ASD and epilepsy. In a recent study, we present the first pre-clinical evidence that CBD can effectively treat autism in these mice.
How do you measure autism behaviours in mice? There are several tests that scientists commonly use to model social behaviour. One test measures the time spent socially interacting with another mouse. When compared to time interacting with an inanimate object, normal developing mice show a strong preference for interacting with the mouse compared to the object. Mouse models of autism are indifferent about spending time interacting with a mouse versus an object. However, when given CBD, our mice gained a preference for socially interacting with the mouse. This test demonstrated that CBD improves social interaction deficits consistent with those seen in children with ASD, but it didn’t inform us of CBD’s effects on the quality of the interaction.
To gain insight into the qualitative elements of social interaction, we placed two mice in a square testing chamber simultaneously and allowed them to freely explore the chamber and interact with each other. In this test, ASD mice would frequently dart away from their social interaction and huddle in the corner of the chamber. We interpreted this to be a measure of social anxiety, which was likely, in part, driven by overwhelming sensory stimuli. CBD was able to normalize this abnormal escape behaviour. These results reveal CBD’s potential to reduce autism-like impairments in social interaction and social anxiety that are caused by impaired inhibitory GABAergic signalling in the brain, which is a common underlying feature of ASD.
These improvements in social behaviours were associated with CBD’s ability to enhance inhibitory brain function by increasing the activity of the neurons that regulate the level of inhibition in the brain. By restoring this excitatory/inhibitory balance in the brain, CBD can reduce seizures and normalize social behaviour…at least in mice.
To date, there is only one clinical trial looking at CBD’s effectiveness in ASD which is being led by Dr. Adi Aran from the Shaare Zedek Medical Center in Jerusalem, but that trial isn’t expected to be completed until July 2019. However, there’s amassing parental anecdotal evidence that CBD eases many of their children’s ASD symptoms. Anecdotal reports aren’t sufficient to cause a shift in the medical community’s ASD treatment strategy, but they certainly justify further investigation. Combined with the recent pre-clinical data, there’s reason to be excited about the future of cannabis for ASD treatment.