Autistic Spectrum Disorder (ASD) is a developmental disorder characterized by persistent deficits in social interaction, repetitive behaviors, and language delay. The disorder can also be associated with symptoms of anxiety and hyperactivity, among other features. ASD is ubiquitous and is estimated to affect 1 in every 54 children. Although early treatments with therapy such as Applied Behavioral Analysis (ABA) have improved outcomes, there is currently no cure for ASD. Approved pharmaceutical therapies for specific symptoms may not be very effective and can carry significant side effects. Recently, the efficacy of cannabis in treating a wide variety of conditions, including certain mental health disorders, has been investigated. In May 2021, a systematic review of research examining the use of cannabis in the treatment of ASD was published.
In October 2020, a thorough search of four scientific databases was performed and yielded a total of nine articles after inclusion and exclusion criteria were applied. Studies evaluating the impact of cannabis to treat specific behavioral symptoms of ASD demonstrated improvement. One retrospective analysis showed significant improvement in anxiety and communication. Another study reported improvements in anxiety, irritability, and hyperactivity with few adverse side effects. Of studies reviewed, side effects occurred with a frequency of about 2% to 14%. Aside from a psychotic episode in one child, no severe side effects were reported. This symptom was temporary and resolved in 9 days.
One study evaluated changes in brain activity following CBD administration in patients with ASD using functional MRI imaging. Results demonstrated that the brains of those with autism respond differently to certain types of neurotransmitters. Such studies are valuable as they lead to a better understanding of pharmacologic targets for the treatment of ASD.
Although these results are promising, it is important to note the limitations of this review. For one, all randomized, double-blind studies reviewed neuroimaging and did not focus on what these findings translate to clinically. In addition, sample sizes were small, and all evaluations were either retrospectively or prospectively observational. However, results provide support for the future development of well-designed randomized controlled trials. In addition, a more thorough evaluation of how cannabis may impact specific neurotransmitter systems in those with ASD is undoubtedly warranted as it may lead to the discovery of novel drug targets.