Autism – Medical Marijuana Research Overview

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Autism is a neurodevelopmental disorder that develops in infancy or childhood. The disorder is characterized by social interaction and communications impairments, as well as restricted and repetitive behaviors. Studies have shown cannabis is effective at improving behavior and communication abilities by repairing the brain’s ability to send clear signals.

Overview of Autism

Autism spectrum disorder (ASD) is a term used to classify a range of complex neurodevelopment disorders that are characterized, in varying degrees, by social interaction difficulties, verbal and physical communication problems, and restricted and repetitive patterns of behavior. Of the numerous types of ASD’s is autism, also referred to as “classical ASD.” Autism is the most severe form of ASD. Other types of ASD’s include Asperger syndrome, childhood disintegrative disorder, and pervasive developmental disorder-not otherwise specified. According to the National Institute of Neurological Disorders and Stroke, 1 out of 88 children age 8 will have an ASD and males are four times more likely to have one of the disorders than females.

Impaired social interaction is the main sign of ASD and it can become visible as early as infancy. Babies and children with ASD can be unresponsive to people, avoid eye contact or fail to respond to their names. They may focus on one item for a long period of time without noticing any outside stimulation. They struggle at interpreting the thoughts and feelings of others and therefore have problems understanding and responding to social cues like facial expressions and tone of voice. It’s not uncommon for them to lack empathy. Repetitive motions like rocking or twirling, or self-abusive behaviors, like biting or head banging, are common in children with autism.

Very early indicators of an ASD include not responding to one’s name, poor eye contact, no babbling or pointing by age 1, no single words by 16 months, excessive lining up of toys or other objects and no smiling or social responsiveness. Later indicators include an impaired ability to make friends, difficulty initiating or sustaining a conversation, impaired imaginative play, repetitive or unusual language, restricted patterns of focus and the inflexible need to stick with routines.

The causes of ASD are unknown, but according to the National Institute of Neurological Disorders and Stroke, both genetics and environment likely play a role. Brain irregularities and abnormal neurotransmitter levels are commonly found in ASD infants and children, which suggest that the disease is caused by a disruption in normal brain development because of the presence of gene defects that regulate how brain cells communicate.

Currently, there is no cure for ADS, so traditional treatment focuses on skill-oriented training interventions to teach social and language skills, medications for anxiety, depression or obsessive-compulsive behaviors.

Findings: Effects of Cannabis on Autism

Researchers have found what they believe to be a potential link between autism and the cannabinoid 2 receptors (CB2) within the endocannabinoid system. One study found that the cell mutations in the brain that have been previously associated with autism block the action of molecules that act on CB2 receptors. These CB2 receptors are the same ones that the cannabinoids found in cannabis, tetrahydrocannabinol (THC) and cannabidiol (CBD) act upon2. A similar study also found that mice with autistic-like behavioral issues possessed upregulated CB2 receptors5. Another discovered this same prevalence in the upregulation of CB2, but in human subjects6. These findings regarding the CB2 receptors support the theory that autism could be caused by a disruption of the brain’s ability to send clear signals and in turn raises the possibility that using cannabinoids found in cannabis can restore communication to allow for proper cell function and communication2.

There’s also evidence supporting cannabinoids efficacy for treating autism. In one study, an autistic child that was given THC for six months reported significant improvements in hyperactivity, lethargy, irritability, stereotypy and inappropriate speech4. In addition, mice with similar behavioral characteristics to autistic humans saw a reduction in depression and were able to remain focused on running on the spinning wheel apparatus after given cannabinoids5. Another study found that boosting cannabinoids like the ones found in marijuana in the brain helps to correct behavioral issues that are related to fragile x syndrome, the most common known genetic cause of autism3.

States That Have Approved Medical Marijuana for Autism

Pennsylvania is the only state to have approved medical marijuana for autism.

A number of other states do, however, consider allowing marijuana for conditions that are not specified in their list of approved conditions. An approval or physician recommendation is required for consideration. These states include: California (any debilitating illness where the medical use of marijuana has been recommended by a physician), Connecticut (other medical conditions may be approved by the Department of Consumer Protection), Massachusetts (other conditions as determined in writing by a qualifying patient’s physician), Nevada (other conditions subject to approval), Oregon (other conditions subject to approval), Rhode Island (other conditions subject to approval), and Washington (any “terminal or debilitating condition”).

In Washington D.C., any condition can be approved for medical marijuana as long as a DC-licensed physician recommends the treatment.

Studies on Cannabis’ Effect on Autism
  • An autistic child given THC for six months reported significant reductions in the symptoms of autism.
    Use of dronabinol (delta-9-THC) in autism: A prospective single-case-study with an early infantile autistic child.
  • Mice with similar behavioral characteristics to autistic humans saw an enhanced reduction in depression and were able to remain focused on running on the spinning wheel apparatus.
    Consequences of cannabinoid and monoaminergic system disruption in a mouse model of autism spectrum disorders.


  1. Autism Fact Sheet. (n.d.). National Institute of Neurological Disorders and Stroke. Retrieved from
  2. Foldy, C., Malenka, R.C., and Sudhof, T.C. (2013, May 8). Autism-associated neuroligin-3 mutations commonly disrupt tonic endocannabinoid signaling. Neuron, 78(3), 498-509.
  3. Jung, K.M., Sepers, M., Henstridge, C.M., Lassalle, O., Neuhofer, D., Martin, H., Ginger, M., Frick, A., DiPatrizio, N.V., Mackie, K., Katona, I., Piomelli, D., and Manzoni, OJ. (2012). Uncoupling of the endocannabinoid signalling complex in a mouse model of fragile x syndrome. Nature Communications, 3:1080. doi: 10.1038/ncomms2045.
  4. Kurz, R., and Blass, K. (2010). Use of dronabinol (delta-9-THC) in autism: A prospective single-case-study with an early infantile autistic child. Cannabinoids, 5(4), 4-6.
  5. Onaivi, E.S., Benno, R., Halpern, T., Mehanovic, M., Schanz, N., Sanders, C., Yan, X., Ishiguro, H., Liu, Q.R., Berzal, A.L., Viveros, M.P., and Ali, S.F. (2011, March). Consequences of cannabinoid and monoaminergic system disruption in a mouse model of autism spectrum disorders. Current Neuropharmacology, 9(1), 209-14.
  6. Siniscalco, D., Sapone, A., Giordano, C., Cirillo, A., de Magistris, L., Rossi, F., Fasano, A., Bradstreet, J.J., Maione, S., and Antonucci, N. (2013, November). Cannabinoid receptor type 2, but not type 1, is up-regulated in peripheral blood mononuclear cells of children affected by autistic disorders. Journal of Autism and Developmental Disorders, 43(11), 2686-95.
  7. What Is Autism? (n.d.). Autism Speaks. Retrieved from

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