Autism spectrum disorder (ASD) refers to a group of neurodevelopmental disorders, the symptoms of which include impaired communication and social interaction with restricted or repetitive motor movements. In some instances, it may also be associated with general cognitive deficits. Although ASD can be diagnosed at any age, it is defined as a “developmental disorder” because symptoms typically manifest within the first two years of life. Autism is known as a spectrum disorder because its symptoms can range from mild to debilitating.
Modulation of the endocannabinoid system has been suggested as a target for ASD therapies, and children with ASD have been found to possess lower-than-normal levels of certain endogenous cannabinoids, including anandamide.
In recent years, a growing number of human studies and case reports have documented improvements in ASD patients following the administration of various cannabinoid formulations.
For instance, a 2019 Brazilian observational trial reported that the twice-daily administration of plant-derived CBD extracts was associated with improved ASD symptoms in 14 out of 15 adolescent subjects.
A series of Israeli trials have also documented favorable results. In 2018, researchers reported to the journal Neurology that the administration of CBD-dominant cannabis extracts led to significant improvements in over 60 percent of ASD patients with refractory behavioral problems.
A 2019 study involving 188 patients reported that over 90 percent of subjects who were administered CBD-dominant extracts for a period of at least six months demonstrated “some level of symptomatic improvement.” Approximately one-third of respondents reported a reduction in their intake of other medications. Authors concluded, “Cannabis as a treatment for autism spectrum disorders patients appears to be well-tolerated, safe, and [an] effective option to relieve symptoms, mainly: seizures, tics, depression, restlessness, and rage attacks.”
Yet another Israeli trial completed the same year similarly reported that the use of CBD extracts resulted in “overall improvements” in a cohort of 53 children with ASD.
In 2020, US researchers affiliated with Tufts University in Boston reported on their clinical experience working with children and young adults with ASD who had consumed either cannabis or hemp-based products. Among subjects with ASD-associated aggression, 60 percent reported improvements following treatment. Among subjects diagnosed with both ASD and epilepsy, 91 percent reported some improvement in seizure control.
The following year, Canadian researchers documented the successful treatment of a 15-year-old patient with autism after adding low doses of CBD/THC extracts adjunctively. Researchers reported that the patient’s symptoms improved within six months of treatment, and that he had experienced “positive effects on his behavioral symptoms, anxiety, sleep, and social deficits” since that time.
Also in 2021, a team of Turkish researchers reported on the long-term use of CBD-dominant extracts in a cohort of 33 adolescent subjects diagnosed with mild-to-severe autism. Authors reported: “[M]ain improvements of the treatment were as follows: a decrease in behavioral problems was reported in 10 patients (32.2 percent), an increase in expressive language was reported in 7 patients (22.5 percent), improved cognition was reported in 4 patients (12.9 percent), an increase in social interaction was reported in 3 patients (9.6 percent), and a decrease in stereotypes was reported in 1 patient (3.2 percent). The parents reported improvement in cognition in patients who adhered to CBD-enriched cannabis treatment for over two years.” They concluded, “Using lower doses of CBD and trace THC seems to be promising in managing behavioral problems associated with autism.”
In more recent clinical trials, the administration of whole-plant cannabis extracts have demonstrated safety and efficacy compared to placebo. In a 2021 Israeli placebo-controlled trial involving 150 adolescents with autism, researchers reported: “In this study, we have demonstrated for the first time in a placebo-controlled trial that cannabinoid treatment has the potential to decrease disruptive behaviors associated with ASD, with acceptable tolerability. … Disruptive behavior on the CGI-I [Clinical Global Impression-Improvement scale] was either much or very much improved in 49 percent [of subjects taking] whole-plant extract versus 21 percent on placebo. Median SRS [Social Responsiveness Scale] Total Score (secondary-outcome) improved by 14.9 [points] on whole-plant extract versus 3.6 points after placebo.”
Placebo-controlled, randomized clinical trial data from Brazil showed similar efficacy. Researchers evaluated the use of CBD extracts versus placebo in 60 children (ages 5 to 11) with ASD over a 12-week period. Compared to the placebo group, subjects receiving CBD extracts experienced significant improvements in their ability to engage in social interactions. They also experienced reduced anxiety and agitation. Only a minority of subjects administered CBD exhibited adverse events, namely dizziness and insomnia.
Australian researchers are currently conducting their own clinical trials, and they have reported “significant changes” in patients’ symptoms and behaviors in their initial data.
Survey data published by the publication Autism Parenting Magazine reported that 22 percent of US caregivers or parents have provided CBD to an autistic child. Survey data from the United Kingdom reported that autistic adults were nearly four times as likely as controls to report having used CBD within the past year.
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