Autism and Cannabis: Here’s What the Science Says

Published on June 20, 2018 · Last updated October 5, 2021

Many parents have seen firsthand the calming, clarifying effect that cannabidiol (CBD) has on their autistic children. Yet most mainstream medical professionals remain skeptical about the effectiveness and safety of using medical cannabis to treat autism. Even politicians are divided: Earlier this month Colorado Gov. John Hickenlooper vetoed a bill passed by the state legislature that would have added autism as a condition that qualifies for medical cannabis.

What does the science say? Like many conditions treated with medical marijuana, the personal experience and anecdotal evidence currently runs far ahead of the peer-reviewed scientific research.

Autism is often accompanied by epilepsy, leading some to suspect that CBD could allay both conditions.

It doesn’t help that headlines around the issue tend to reek of reefer madness (“Desperate Parents Of Autistic Children Trying Cannabis Despite Lack Of Studies”) or sensational cures (“Marijuana may be a miracle treatment for children with autism,”Why I Give My 9-Year-Old Pot”).

Autism Spectrum Disorders (ASDs) are lifelong neurodevelopmental conditions that involve differences in language, behavior, and social interaction. It’s worth acknowledging that autism can be a highly contentious issue. The very definition of ASD/autism can spark debate among parents and experts. An emerging neurodiversity movement, for instance, has coalesced around the idea that conditions such as autism, ASD, and ADHD aren’t pathologies to be treated but differences to be respected. Autism has long been defined as a cognitive deficit. For those in the neurodiversity movement, it’s a cognitive difference.

In April, the federal Centers for Disease Control increased its autism prevalence estimate among 8-year olds, to 1 in 59 children nationwide. (Graph courtesy of Autism Speaks)

Parents Searching for Relief

Brandy Williams’ experience is typical of the parents who use medical cannabis as part of their child’s treatment. Williams is the parent of an 8-year-old son, Logan, who was diagnosed with ASD a few years ago. By the age of five, Logan had exhibited countless examples of aggressive behavior: biting her, banging his head more than 150 times a day, and worse. Logan had even knocked out his own teeth—twice. Williams tried nearly 50 hours of therapy, but it didn’t seem to help.

In addition to ASD, Logan also suffered from epileptic seizures. That’s not unusual among people living with autism. Researchers have noted that ASD is often accompanied by other neurological disorders, which could arise from an underlying central nervous system condition.

Epilepsy is commonly reported to occur in about one-third of people with ASD, but scientific studies have turned up a wide spectrum of co-morbidity ranging from 5% to 46%.

In Logan’s case, his epilepsy diagnosis actually helped his overall situation with regard to medical marijuana.

Autism as a Qualifying Condition

Autism is a qualifying condition in these states:Cannabis may be recommended by doctors for many conditions, including autism, in these states:
GeorgiaDistrict of Columbia
South Carolina

In Arizona, Epilepsy Qualifies

Williams and her son live in Arizona, one of the many medical marijuana states that do not include autism as a condition that qualifies for medical cannabis. Arizona does include epilepsy on the list, however. (Leafly has a full list of Arizona’s qualifying conditions here.)

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Years ago Logan’s mother tried to calm his symptoms by giving him hemp-derived CBD. That proved ineffective. But in June 2014, Arizona legalized the use of medical-grade cannabis for pediatric epilepsy patients. So Williams obtained a medical marijuana card for her son.

After a single dose of oil containing terpenes, CBD, and other cannabinoids (including a tiny amount of THC), Williams noticed a tremendous difference. Logan stopped rocking back and forth. His flapping hands calmed. After being completely nonverbal, Williams recalled, “Logan said 180 words in the first two months” of medical cannabis therapy.

Brandy Williams is one of many parents who have found medical cannabis to be effective in treating their child’s condition. Yet autism has yet to be accepted as one of the foundational conditions that qualify for medical marijuana in the 30 states that legally allow healthcare professionals to recommend it.

Only five states—Delaware, Pennsylvania, Minnesota, Georgia, and South Carolina—specifically include autism as a qualifying condition. A few others, including Michigan, California, Massachusetts, and the District of Columbia, don’t specifically include autism but allow doctors to recommend medical cannabis at their discretion as they see fit. Some parents of autistic children have accessed medical cannabis for their child to treat a qualifying co-morbid condition (such as muscle spasms or pain) and found that the cannabis allays some of the negative symptoms of autism as a side benefit.

Williams and her local chapter of MAMMA (Mothers Advocating Medical Marijuana for Autism, a group with active chapters in six states) have pushed Arizona regulators to add autism to the state’s MMJ list, but they’ve met with resistance from state officials.

Most states don’t allow it, and yet some parents are adamant in their belief that it works. Why the disparity? Because the published research on cannabis and autism isn’t thin, vague, or contradictory. It’s practically nonexistent.

A 2015 Baseline Study

Three years ago, three scientists associated with Boston Children’s Hospital and Harvard University published what has become the baseline review of studies on cannabis and autism. They found research that showed slight promise, but nothing that definitively connected cannabis to an improvement in pediatric patients.

The Boston study (click to access).

“At this time, good evidence is almost entirely lacking for its application in pediatric developmental and behavioral conditions,” wrote Scott Hadland, John Knight, and Sion Harris in the Journal of Developmental and Behavioral Pediatrics.

“Many advocates cite scientific literature regarding benefits of cannabis for the treatment of pediatric behavioral conditions,” they added, “but often, data cited are from animal model-based research that does not yet have translation to human subjects.”

They mentioned that:

  • A 2013 study from Stanford University showed that mice with a specific and rare gene mutation linked to autism showed altered endocannabinoid signaling in the central nervous system. These data were then cited by online and print media supporters of medical marijuana (for example, in the High Times) as evidence that cannabis could be used as a treatment for autism.
  • Another recent study based on a mouse model…showed alterations in endocannabinoid signaling pathways. These data were referenced (in this case, by more mainstream media outlets, such as the Huffington Post and Fox News) as evidence for a promising role for cannabis as treatment.

“Although these and other high-impact studies share important insights into the pathogenesis of ASD and fragile X syndrome, based on their results alone, it is erroneous and potentially harmful to conclude that cannabis should be used as treatment for either of these disorders at this time.”

“Given the current scarcity of data,” the authors conclude, “cannabis cannot be safely recommended for the treatment of developmental or behavioral disorders at this time. At best, some might consider its use as a last-line therapy when all other conventional therapies have failed.”

Cautious Authors

That’s a pretty strong cautionary statement. At the same time, it’s worth noting that Scott Hadland, the study’s lead author, has written many previous studies that view cannabis solely through the lens of addiction and youth substance abuse. He’s not done any firsthand research into the medical use of cannabis on autism or any other condition.

The conclusions of Hadland and his colleagues may ultimately prove to be overly cautious—or they may be wise words of advice. At the very least, if you’re a parent or patient talking with a physician about cannabis and autism, you should be aware that the Hadland overview is one of the main documents that mainstream doctors will be consulting.

Aside from anecdotal reports like those from Brandy Williams, what makes some in the autism community hopeful about the possibilities of cannabis as a healing agent?

Mostly it boils down to the potential links between epilepsy and autism. And when it comes to epilepsy and cannabis, there actually have been a number of peer-reviewed studies.

While only 2% of the general population suffers from epilepsy, one-third to one-fifth of people with autism suffer from epileptic seizures, according to a 2009 study by researchers at the National Institute of Mental Health.

“There’s definitely an association,” between autism and epilepsy, says Dr. Thomas Deuel, a neuroscientist who is an epilepsy specialist at Swedish Hospital in Seattle. “It’s not known why. The different brain development that occurs in autism is epileptogenic, meaning it’s more likely to create circuits that can cause seizures. Autistic brains develop differently.”

The link between epilepsy and autism led many parents like Brandy Williams to look into how medical cannabis might affect their child’s condition.

How Does Cannabis Consumption Affect Autism?

Cannabis Can Calm Seizures

Many—but not all—who have administered cannabis to epileptic children have seen promising results.

One of the earliest reports about the effects of cannabis on epilepsy involved Charlotte Figi, a young Colorado girl whose case later became world-famous.

Years ago, Figi suffered from a drug-resistant form of epilepsy called Dravet’s syndrome. Her seizures, which began when she was an infant, would sometimes last hours, and caused repeated heart failures. Sometimes she had hundreds of them in a week.

Her parents, after hearing of another boy helped by cannabis, gave her oil derived from a low-THC, high-CBD cannabis strain developed by the Stanley brothers, seven Colorado brothers who would go on to found the company Charlotte’s Web.

After ingesting the oil, Figi’s seizures slowed to a crawl. Her success led others to take a closer look at cannabis oil, and specifically at low-THC, high-CBD varieties of the plant.

Epilepsy Research Evolves

Orrin Devinsky, MD, a neurologist at the New York University Langone Medical Center, has been studying the effects of CBD on epilepsy. His recent study of Epidiolex, a drug under development by GW Pharmaceuticals, found that the medication reduced the frequency of seizures in epilepsy patients by as much as 42%.

May 2018 NEJM study

In that study, published in May 2018 by the New England Journal of Medicine, one hundred and sixty two people were treated with 99 percent CBD—in addition to their already existing medications. While two percent became seizure free and 36.5 percent had reduction in seizures (similar to the rate of other drugs), many (79 percent) reported side effects like diarrhea, sleepiness, and fatigue. As Scientific American writes, “CBD is a potent liver enzyme inhibitor it can increase the concentration of other drugs in the body,” but because the study didn’t have a control group and it allowed for the patients to continue on their already prescribed drugs.

Devinsky told Scientific American: “I think, based on the evidence that we have, if a child has tried multiple standard drugs and the epilepsy is still severe and impairing quality of life, then the risks of trying CBD are low to modest at best,” Devinsky says. “[But] I do feel it is critical for us as a scientific community to get [more] data.”

CBD is the main active ingredient in Epidiolex, which is expected to receive final approval from the US Food and Drug Administration later this year.

Study Finds CBD Drug Epidiolex Reduces Seizures by 42%

The First Autism Studies

Researchers are only just now digging in to find out how cannabis can help those with autism.

In fact, two of the first such studies are being conducted by Orrin Devinsky, the same NYU neurologist who carried out the recent work on CBD (as Epidiolex) and epilepsy.

The double-blind study of 100 patients will include subjects between five and 18 years old with moderate to severe (4 or higher) autism. The study, done at the Montefiore Medical Center with Dr. Eric Hollander, will be examining the effects of CBDV, or cannabidivarin, which is similar to CBD, on the autistic patients. After the study is finished, the two doctors will conduct another trial involving CBD at New York University, Devinsky told Live Science. 

Devinsky’s study is one of only two autism-and-cannabis projects listed on Clinicaltrials.gov, a database maintained by the National Institutes of Health. There are hundreds of studies worldwide exploring cannabis and various health effects, but only Devinsky’s and one other (run by Shaare Zedek Medical Center in Israel) specifically target autism and cannabis—and according to clinicaltrials.gov, they have yet to begin.

That may soon change. At the recent AutismOne national conference, Ronald Aung-Din, M.D gave a presentation, “The Neuromodulation: Treating Autism w Non-Systemic Direct Effects™ Cannabidiol” espousing the benefits of CBD on autistic patients, using “Direct Effects,” a trademarked topical CBD therapy.

Other research is being jump-started with significant funding. The University of California at San Diego, which has done a number of medical marijuana studies over the past two decades, recently received a $4.7 million gift for medical cannabis research specifically targeting how autism may be affected by cannabinoids.

The gift, from the Ray and Tye Noorda Foundation, is the largest private gift for cannabis research in the country.

“The more severe manifestations of autism are difficult to treat, causing parents to look for non-traditional remedies,” said Igor Grant, MD, professor of psychiatry and CMCR director in a press release. “There are unconfirmed reports that cannabidiol could be helpful, but there are no careful studies to document either its benefits or its safety.”

The 2017 Chilean Study

One report that sits somewhere between anecdotal report and careful study came out in Sept. 2017, at the World Congress of Neurology in Kyoto, Japan. Gisela Kuester, a neurologist specializing in the diagnosis and treatment of autism, presented a paper poster that reported positive results from a very small retrospective look at patients with ASD who were treated with cannabis extracts.

In a very small observational study, most patients given a CBD-THC tincture daily for three months ‘improved at least one of the core symptoms of ASD.’

Kuester is the Clinical Research Director at Fundación Daya, a Chilean nonprofit that promotes research into alternative medical treatments. Her poster reported that 21 patients (20 children and one adult) with ASD were treated with a daily dose of sublingual whole plant cannabis extracts (typically liquid 1:1 CBD:THC tinctures) for at least three months, between June 2016 and March 2017. No specific dosing information was included in the poster.

“Most cases improved at least one of the core symptoms of ASD,” Kuester reported, “including social communication, language, or repetitive behaviors. Additionally, sensory difficulties, food acceptance, feeding and sleep disorders, and/or seizures were improved in most cases.”

The oral extracts were well tolerated by most patients. Two patients exhibited more agitation, and one had more irritability, but those effects, Kuester wrote, were solved by changing the cannabis strain given to the patient.

The written record of that 2017 Chilean study can be found here.

Why Hasn’t It Been Studied More?

“I think it has a lot to do with children,” says neurologist Thomas Deuel. “It’s harder to study things in children than adults. Most of the epilepsy and cannabis studies have been with adults.”

“People are very particularly worried about affecting brain development in children with marijuana,” he adds.

Indeed, the American Academy of Pediatrics (AAP) officially opposes the legalization of cannabis—so much so that the organization recently reaffirmed its opposition in a press release.

Though it advocates for decriminalization, Seth D. Ammerman, MD, FAAP, a member of the AAP Committee on Substance Abuse, said: “We know marijuana can be very harmful to adolescent health and development. Making it more available to adults—even if restrictions are in place—will increase the access for teens. Just the campaigns to legalize marijuana can have the effect of persuading adolescents that marijuana is not dangerous, which can have a devastating impact on their lifelong health and development.”

Adding Autism as a Qualifying Condition

Over the past few years, advocates with MAMMA have successfully pushed lawmakers and state officials to add autism spectrum disorder (ASD) as a qualifying condition in states such as Pennsylvania, Minnesota, and Georgia. But Brandy Williams and other MAMMA activists haven’t yet broken through in Arizona.

Officials at the Arizona Department of Health Services, Williams said, considered her petition to include ASD “too broad.”

They keep referring to this evidence pyramid, and how studies are designed, and blah blah blah,” she said. “But even our pharmaceutical medications are not being held to the standards that they’re requiring to add a [medical cannabis] condition.”

Add in a dose of reefer madness, and you’ve got the perfect formula for no forward momentum. “We’ve already got Arizona Department of Health to admit that the reason why they don’t approve these petitions is because they do not want to give the public the perception that these government health regulatory agencies are proving these conditions and recommend the use of cannabis for those conditions,” Williams said.

The next Arizona Department of Health Services hearing on MAMMA’s petition is scheduled to take place in June.

Meanwhile, in Texas, the Lone Star State’s chapter of MAMMA (pictured below) lobbied members of the GOP at their annual state convention last week. The state party voted to not only expand the extremely limited Texas Compassionate Use Act, but also to decriminalize cannabis entirely.

Altering the ‘Attentional Spectrum’

Endocannabinoids can help regulate hunger, anxiety, neuronal excitability, protection and pain, among other things. With epilepsy, cannabidiol (CBD) can help suppress seizures. Those who look to cannabinoid medicine to help with autism believe that it can help bring order to a brain that’s a live wire.

“Kids with autism, adults with autism” says Deuel “have a lot of focus and attentional issues. They’re not clued into a lot of their surroundings, but they’re very clued into one thing that they kind of get obsessed about. So I think that when you give an autistic child cannabis, it alters their attentional spectrum.”

That—at least anecdotally—is what Brandy Williams and other parents who have administered cannabis to their ASD kids have noticed. For Williams’ son, Logan, cannabis did what 47 hours of weekly therapy couldn’t. She still recalls that first night with wonder. “He came up and he sat down next to me and watched a movie for the first time in his life.”

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Tricia Romano
Tricia Romano
Tricia Romano is the former editor in chief of The Stranger. She previously worked as a staff writer at the Seattle Times, and has been published in the New York Times, Elle.com, Rolling Stone, the New York Post, New York magazine, Slate, Grantland, Spin, and Salon. She covered underground culture in New York City for the Village Voice for eight years in her column “Fly Life.”
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