Cannabis and autism, explained
by Peter Hess / 7 September 2020
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Over the past decade, autistic people and their families have increasingly experimented with medical marijuana and products derived from it. Many hope these compounds will alleviate a range of autism-related traits and problems. But scientists are still in the early stages of rigorous research into marijuana’s safety and effectiveness, which means that people who pursue it as treatment must rely mostly on anecdotal information from friends and message boards for guidance.
Here we explain what researchers know about the safety and effectiveness of cannabis for autism and related conditions.
What is medical marijuana?
Medical marijuana generally refers to any product derived from cannabis plants — including dried flowers, resins and oils — that has been recommended by a doctor. It may be consumed directly or infused into an array of foods, lozenges and candies. These products have become popular among autistic people and their families for treating a broad swath of conditions, including insomnia, epilepsy and chronic pain.
Depending on the strain of the plant and the processing methods used, these products contain varying levels of active ingredients, including tetrahydrocannabinol (THC) — responsible for the ‘high’ associated with marijuana — and cannabidiol (CBD), which is minimally psychoactive. Much of the research on medical applications focuses on CBD. There are also more than 500 other compounds in marijuana that may affect people’s behavior and cognition 1 .
Is medical marijuana legal?
Yes and no. Federal law in the United States classifies marijuana and its derivatives as ‘Schedule 1’ drugs, meaning that they have no accepted medical use and a high potential for abuse. Schedule 1 drugs are illegal, and research on them requires labs to follow strict security protocols and adhere to regular facility inspections.
In 33 states, along with the District of Columbia and Puerto Rico, however, people can legally buy and use medical cannabis for certain approved conditions, such as seizures and sleep problems, although the list of qualifying conditions varies by state. These same states, plus 13 others, also allow CBD oil. Fourteen states plus Puerto Rico have approved medical marijuana for autism, and some additional states may allow it for autistic people at a doctor’s discretion.
Under U.S. federal law, CBD products manufactured from industrial hemp are legal as long as they contain no more than 0.3 percent THC. And in some states, CBD oil is permitted to contain up to 5 percent THC.
In many states where medical marijuana is legal, licensed dispensaries sell products that have been tested by accredited laboratories to verify the presence of active ingredients and the absence of contaminants. Some states permit individuals or their licensed caregivers to grow their own cannabis plants for personal use. Most states in the U.S. require people who use medical marijuana to register and get a special identification card.
In many European countries, as well as in Australia, Canada, Israel and Jamaica, medical cannabis is legal, with specific laws varying from country to country.
Are there any cannabis-derived drugs approved to treat autism or related conditions?
To date, the U.S. Food and Drug Administration has approved only one cannabis-derived drug: Epidiolex. It is a liquid cannabis extract containing purified CBD that can decrease seizures in people with Dravet syndrome or Lennox-Gastaut syndrome — severe forms of epilepsy that are sometimes accompanied by autism — and in those with tuberous sclerosis complex. It is available only by prescription, and only for these three conditions.
GW Pharmaceuticals, the company that makes Epidiolex, is conducting a trial of the drug for Rett syndrome, a neurodevelopmental condition related to autism. The Rett syndrome trial is not focused on alleviating seizures, but on improving cognitive and behavioral problems. The company is also recruiting autistic children and teenagers for a phase 2 trial of cannabidivarin, another component of cannabis. That trial will examine cannabidivarin’s effect on a range of traits in autistic children, including repetitive behaviors, and on quality of life.
How might cannabis help autistic people?
Epidiolex’s success has spurred many parents to try marijuana and cannabis extracts for seizures, behavioral issues and other autism-related traits in their children, but experts warn that these drugs remain largely untested for such purposes. Some studies on cannabinoids have shown promising results in animal models and in early-stage clinical trials, but this research does not yet support their widespread use.
Cannabis’ active ingredients are thought to exert their effects by binding to proteins called cannabinoid receptors in the brain: THC activates the CB1 and CB2 receptors, whereas CBD seems to block them 2 .
Both types of cannabinoid receptors are located in neurons in the brain and throughout the body. The brain contains more CB1 than CB2 receptors, and the activation of each receptor type affects a range of ion channels and proteins involved in cell signaling 3 . The ultimate effects of cannabinoid receptor activation depend on which body system they belong to. For instance, the activation of CB1 receptors in the brain can either increase or decrease neuron excitability, depending on which kind of neuron a cannabinoid binds to; activation of CB2 receptors in the digestive system can decrease inflammation 4,5 .
Blocking the CB1 receptor can relieve seizures and memory issues in a mouse model of fragile X syndrome, a condition related to autism, according to a 2013 study in Nature Medicine 6 . A 2018 clinical trial of a synthetic CBD drug by the drug maker Zynerba showed significant improvements in anxiety and other behavioral traits in people with fragile X. Cannabinoid receptor activation has also been shown to lead to memory improvements in fragile X mice 7 .
Research has also demonstrated that CBD alleviates seizures in children with CDKL5 deficiency disorder, an autism-linked condition that is characterized by seizures and developmental delay. CBD also lessens seizures and improves learning and sociability in a mouse model of CDKL5 deficiency disorder.
Complicating the picture, CBD alone may not be sufficient for cannabis’ therapeutic effects. A 20-to-1 ratio of CBD to THC relieves aggressive outbursts in autistic children, a 2018 study suggests 8 . This same ratio of compounds significantly improved quality of life for some children and teenagers with autism in a 2019 study 9 . Specifically, researchers observed significantly fewer seizures, tics, depression, restlessness and outbursts. Most participants reported improvements, and about 25 percent of participants experienced side effects such as restlessness.
Cannabis may have effects that go beyond the cannabinoid receptors, too. Mice that ingested CBD over extended periods of time displayed changes to DNA methylation in sections of the genome associated with autism, a 2020 study showed 10 . The researchers suggested that epigenetic changes may be at least partly responsible for CBD’s behavioral effects, though they did not directly examine the mice’s behavior.
Is cannabis safe?
It’s unclear. Large doses are usually not fatal, but taking it regularly may have long-term effects.
Based on the clinical trials of Epidiolex, the FDA warns that the drug could cause elevated liver enzymes, which can be a sign of liver damage. This is especially likely in people who take Epidiolex and the epilepsy drug valproate at the same time.
CBD is considered minimally psychoactive, but many preparations of it contain undisclosed amounts of THC, which may lead to inadvertent intoxication and impairment.
Many studies have shown that cannabis treatment carries only minor side effects such as sedation or restlessness, but these studies have not looked at long-term side effects. Researchers still don’t have a solid grasp on how the active ingredients in marijuana actually affect the brain, nor do they know how these compounds might impact a child or teenager’s developing brain or interact with other medications.
Some research has shown that recreational marijuana use beginning in one’s teenage years can have negative long-term effects on cognition 11 . But experts note that the dosages used for medical purposes are often quite lower than those used in a recreational context.
Are some cannabis products safer or more effective than others?
Many people who self-administer cannabinoids for epilepsy or other conditions cultivate it at home. Others purchase it directly from companies rather than buying it at state-licensed dispensaries, and research has shown that these products are not created equal.
The actual potency of CBD products varies widely from their advertised concentrations, according to a 2017 study in JAMA, and some products contain more than the legal limit of THC — potentially enough to cause intoxication, especially in children 12 . Less than one-third of the products tested contained within 10 percent of the advertised CBD concentration, and THC was detected in about 21 percent of samples.
In a presentation at the 2020 meeting of the American Academy of Neurology, researchers concluded that ‘artisanal’ CBD products available for purchase online and in health-food stores are not as effective at controlling seizures as pharmaceutical-grade CBD.
Autistic people and their families are increasingly experimenting with marijuana to try to ease problems such as insomnia, epilepsy and chronic pain — and traits of autism. But there is little evidence for its safety or effectiveness.
CBD Oil as a Treatment for Autism
Arno Kroner, DAOM, LAc, is a board-certified acupuncturist, herbalist, and integrative medicine doctor practicing in Santa Monica, California.
Cannabidiol , sometimes called CBD, is a chemical compound found in the cannabis plant. Since it does not include THC, the psychoactive component of cannabis, CBD does not induce a “high.” It can, however, help to reduce anxiety and lower stress levels—symptoms that are common among people with autism.
Currently, there is some evidence that CBD can help to alleviate specific symptoms and improve behavior in children and adults on the autism spectrum, but research into the safety and efficacy of CBD is in its earliest stages.
CBD can be derived from hemp or cannabis (the marijuana plant) and is now legal in many states in the United States and in many countries around the world. It can be purchased without a prescription as an oil, tincture, pill, or chewable pill online and is also an ingredient in edibles ranging from coffee to pastries. It comes in many dosages and at many price points.
Claims for CBD range from the realistic to the absurd. Some websites and companies claim, for example, that CBD can cure cancer (it can’t). On the other hand, CBD does seem to alleviate some untractable symptoms of disorders such as epilepsy, sleeplessness, and anxiety—all common issues for people with autism. According to Harvard Health Publishing, “the strongest scientific evidence is for its effectiveness in treating some of the cruelest childhood epilepsy syndromes, such as Dravet syndrome and Lennox-Gastaut syndrome (LGS), which typically don’t respond to antiseizure medications.”
In numerous studies, CBD was able to reduce the number of seizures, and in some cases, it was able to stop them altogether. Recently, the FDA approved the first-ever cannabis-derived medicine for these conditions, Epidiolex, which contains CBD. CBD is commonly used to address anxiety, and for patients who suffer through the misery of insomnia, studies suggest that CBD may help with both falling asleep and staying asleep.”
CBD is not helpful for everyone who uses it, and, in rare cases, it can cause side effects such as sleepiness or nausea.
How CBD May Help People With Autism
Neither CBD nor any other drug can remove or cure core symptoms of autism, which include social communication challenges, sensory dysfunction, and restricted, repetitive behaviors. CBD can, however, help to alleviate disorders often associated with autism such as epilepsy, anxiety, sleeplessness, and stress.
By relieving the associated disorders, CBD may help reduce some of the most problematic aspects of autism.
For example, it may cause better sleep and lower anxiety (which can reduce aggressive behaviors), fewer seizures (which can lessen stress and make it easier to interact socially), and lower anxiety to make it easier to learn and use social communication skills.
It’s also important to note that sleeplessness and aggression are particularly difficult symptoms for parents, who can quickly find themselves exhausted and overwhelmed. Aggression, in particular, is one of the most challenging behaviors common to autism—oftentimes, this is a reason a parent may place their child with autism in an institutional setting.
A few full-scale studies have explored the impact of CBD on children with autism—none, however, have explored its impact on adults on the spectrum. One of the largest such studies took place in Israel. The report includes the following finding:
“In 2014, The Ministry of Health began providing licenses for the treatment of children with epilepsy. After seeing the results of cannabis treatment on symptoms like anxiety, aggression, panic, tantrums and self-injurious behavior, in children with epilepsy, parents of severely autistic children turned to medical cannabis for relief.”
The results of the study were encouraging. Most of the children involved saw improvement in anxiety, anger, and hyperactivity.
In addition (and perhaps as a result), they also saw significant improvements in social communication, sleep, and self-injury (a small percentage, however, worsened with treatment). A tremendous bonus is the fact that there were few side effects, and those that did appear (sleepiness and change in appetite) were mild.
Additional studies have provided similar results: CBD has proved to be helpful in a majority of cases in lessening emotional and behavioral issues and can even help to improve social communication skills. These preliminary findings, along with the low incidence of significant side effects, are very encouraging. Studies are ongoing in clinics and research centers around the world.
Before Trying CBD
Given all of the positive findings for CBD and the low risk associated with it, it may make sense to try using it with your child with autism (or trying it yourself if you are an adult with autism). Before buying a bottle of CBD oil, however, it’s important to follow these steps:
- Check with your child’s (or your) doctor to be sure that no allergies or sensitivities exist that could cause a reaction to CBD.
- Check to be sure that CBD is legal in your state, province, or country.
- Research sources of CBD to be sure the brand you’re using is well-regarded and properly licensed.
- Take careful notes to be sure you have baseline information about your child’s (or your own) behaviors and symptoms so that you can make a useful comparison before and after using CBD.
CBD comes in many forms and at many dosage levels. Oils taste somewhat bitter, which is why many people prefer chewable candy-like options; of course, it’s important to keep candy-like drugs and supplements out of the reach of children.
In general, it’s best to start with a lower dosage. In fact, studies of CBD for other disorders such as migraine suggest that a lower dose may be more effective.
Lower doses are also more easily tolerated than a higher dose.
When you start using any new supplement, drug, or treatment, it’s important to be sure your child’s doctor is aware of the new treatment and has no concerns about it relative to your child’s health as well as let everyone working with your child know that you’ve started something new and ask them to look for and report any changes in behaviors or skills.
Take careful notes of any changes you see yourself so you can easily review your records to determine how helpful the new treatment really is and keep an eye open for any troubling side effects. Be sure to communicate any side effects to a doctor or healthcare professional immediately.
A Word From Verywell
Children with autism grow and learn every day, simply because they are maturing. As a result, there is no simple way to determine whether a change in behavior or an increase in skills is due to a particular treatment or to ordinary maturation. This reality makes it very easy to see a change in behaviors and inaccurately attribute them to the newest treatment you’ve tried. By far, the best way to know whether a particular treatment is truly effective is to be rigorous about evaluating your child before and after its use.
To do this, you’ll need to create or find and use a numerical scale (1 to 5 for instance) to measure your child’s behavior. For example, is today’s angry outburst at a level 1 or a level 5? By carefully evaluating the impact of a new therapy, you can eliminate the likelihood that you’ll make decisions based on wishful thinking rather than on solid evidence.
CBD oil, derived from hemp or cannabis, is emerging as a potential treatment for symptoms related to autism. Learn more about CBD for autism.