Cannabis & CBD Oil As A Treatment For Autism Explained By A Doctor

Cannabinoid medicine may help treat some Autism Spectrum Disorder (ASD) symptoms in both adults and children. It is often used as an adjuvant (complement) to traditional treatments. However, cannabis doesn’t work for everyone and is not a cure for ASD. Learn more below.

Cannabis, CBD Oil & Autism

Autism is a developmental condition that can have different symptoms, severity and effects on each person.   As the popularity of cannabis, CBD in particular, as medicine grows, people often ask if cannabis can treat or cure Autism Spectrum Disorder (ASD). Cannabis will not cure Autism; But, cannabis can help treat certain symptoms of ASD.

In this article, we’ll aim to answer some of the most commonly asked questions about autism and cannabis treatment for autism. To do this, we spoke with Dr Orit Holtzman, a GP experienced with medicinal cannabis. Here are the topics covered.

What is ASD?

Autism Spectrum Disorder is a complex developmental condition that usually involves challenges in social interaction, speech and nonverbal communication. Individuals with ASD, particularly children, may have restrictive and repetitive behaviours. The symptoms often vary from adult to adult or child to child. 

Some people will have very subtle indications or deficits in communication or social interaction. Other people may be almost non-verbal. There is an extensive range of signs and symptoms.

What are some signs of Autism?

Signs and symptoms of ASD in children often relate to social interaction and communication. For example, children may have trouble maintaining conversation or difficulty sharing their interests and emotions. 

You may also notice challenges in understanding and responding to social cues or triggers like facial expressions. Often, individuals with ASD will also have issues developing, maintaining and understanding relationships – potentially having trouble making friends. Children with Autism may exhibit intense interests that are uncommon for a child in the same age range.

Children with ASD may also exhibit restrictive and repetitive patterns of behaviour, interests or activities. For example, children may regularly have behaviour such as hand flapping or toe walking. They may play with toys in an unusual way, such as lining things up or flipping toys and throwing them around. 

With speech or verbal cues, children may speak uniquely or use specific or odd patterns of speech or scripts from their favourite shows. 

Very often, individuals with Autism will have a significant need for strict routine or rhythm and may become very distressed when you divert from that structure. They may also be indifferent or insensitive to pain or temperature or exhibit excessive smelling and touching objects. This can also be the opposite; They may exhibit over sensitivity, especially to loud noises.

When should individuals seek a doctor’s help for Autism?

Parents should seek professional medical help if they have any concern about their child’s development or behaviour. There isn’t a guide; however, if you feel that something is not right or your child isn’t meeting developmental milestones, you should seek help. 

“Going with your gut feel will mean that sometimes you’ll be reassured that nothing is wrong. But, sometimes there will be something that will require early intervention, and your child will benefit from a doctor’s help.”

With regard to adults, Dr Holtzman said, “Some adults have not been diagnosed at an early age which likely means they are on the mild end of the spectrum. If you have an inclination that the way you or someone you love has challenges in the way they relate to others, you can always seek medical or psychological help to see if there is an underlying diagnosis. There may be something that will help you overcome these challenges.”  

Is there an age range when children start to show signs of ASD?

In some children, it can be obvious that they are not meeting developmental milestones. Other children may seem to develop normally until about 18 months or two years of age. Most children are diagnosed between two and a half to three years old. 

How is Autism diagnosed?

In children, ASD can be diagnosed by a paediatrician, a child psychologist or a child psychiatrist. In adults, diagnosis can come from a psychiatrist or a psychologist. 

Diagnosis happens through a range of tests. The individual must meet the diagnostic criteria in the Diagnostics and Statistical Manual Five (DSM 5). A child must have persistent deficits in each of three areas:

  • Social
  • Communication
  • Interaction

And must also have two of four types of restricted, repetitive behaviours. 

“So, for example, there could be a deficit in reciprocity in back and forth communication and a reduced sharing of emotions or interests. There could also be issues with initiating or maintaining communication and social interactions.

For example, with non-verbal communication, there may be difficulty interpreting non-verbal cues such as facial expressions or difficulty making friends. The child might have difficulty with imaginative play or a lack of interest in their peers. 

Restrictive or repetitive patterns of behaviour, interests or activities can be shown by repetitive stereotypical movements or behaviours like hand flapping, walking backwards and forward or lining up toys. Some children are verbal and have echolalia, mimicking or repeating words or phrases that others say or use phrases that are unique to them.”  

Can cannabis treat Autism Spectrum Disorder?

Yes. Cannabis can help treat some of the behavioural issues that are secondary to ASD. There is a possibility that in individuals with ASD, there’s a dysfunction in the Endocannabinoid System. And that dysfunction is one of the underlying causes of Autism or the behaviours that are secondary to the disorder.

It’s important to emphasise that cannabis (including CBD oil) is not a magic cure and will not cure ASD. Cannabinoid treatment for Autism does not work for everyone, and when it does, it usually is quite a long process.

Can CBD (or CBD Oil) help with Autism?

Cannabidiol (CBD) is one of the main cannabinoids in the cannabis plant. The benefit of CBD is that it’s non-psychotropic. It doesn’t cause the “high” sensation that people often associate with cannabis.

CBD interacts with the endocannabinoid system, the cannabinoid receptors (CB1 and CB2), and other receptors in the human body. These receptors are the ones that work with the neurotransmitters, usually manipulated when treating behavioural issues that are secondary to Autism. CBD is also known to help treat anxiety and agitation which individuals with Autism often display.

CBD can also affect receptors outside of the endocannabinoid system that are important for mood and behaviour. The activation of these receptors can affect the neurotransmitters that are:

“For example, CBD affects serotonergic (serotonin) receptors. CBD can activate the receptors and mimic what some anxiolytic (anxiety-reducing) medications do.

CBD also affects the dopaminergic receptors, the dopamine receptors. These receptors are often affected by psychotic medication. So, it’s in this way that CBD can affect agitation and aggression.

There was also a study on children on the Autistic spectrum, which showed a lower concentration of endocannabinoids in their blood than neurotypical children.

CBD inhibits Fatty Acid Amide Hydrolase (FAAH), which degrades one of our endocannabinoids, Anandamide (the bliss molecule). So, if there is some deficiency in the level of the endocannabinoids in children or people on the spectrum, CBD can increase the level of Anandamide, thus helping to rebalance the endocannabinoid system.”

Can THC help with Autism?

THC is quite controversial when it comes to treating children because it’s known to have a psychotropic effect. THC can cause the well known ‘high’ that people often associate with cannabis. However, it’s important to note that THC does not always cause a high. 

“Interestingly, in most studies, even those done on children with Autism, the cannabis formulation used does contain some THC. Usually, it’s a very high CBD and low THC formation in a ratio of 1:20.”

THC’s main action is directly on the cannabinoid receptors. THC can alter behaviour, attention and learning abilities, and it also can impact immune cells. THC can have benefits in reducing inflammation which is important with regard to ASD because it’s thought that neuroinflammation is one of the traits of ASD.

“Now, interestingly, there is one case study from 2010 on a six-year-old child in Austria. The child was treated with dronabinol, which is synthetic THC. And that child actually showed significant improvement in productivity, irritability, stereotypical behaviour, inappropriate speech symptoms and repetitive behaviour. 

Even though they used a high THC formulation, there was quite a bit of benefit. So, I’m [Dr Orit Holtzman] not saying that it’s exactly what we should be doing. Still, there may be a role for THC balanced by CBD in the treatment of Autism related symptoms.”

Treatment considerations for parents

Dr Holtzman said:

“You need to take into consideration that there are possible side effects, although they are usually quite mild, especially with CBD. There are possible interactions with other medications. And, the long-term side effects of medicinal cannabis are unknown. We do not know if there are any long-term effects after using medicinal cannabis for 10 or 20 years. While cannabis has been used for tens of thousands of years, we don’t have recorded medical data. We aren’t able to say that medical cannabis has no long-term effects.

We also don’t know the exact effects of THC on the developing brain. Research shows that high dose THC in the adolescent brain may cause problems, but nothing that shows positives or negatives at low medical doses. 

Before sharing some of the benefits I’ve seen in treating children, I want to remind you that cannabis is not a magic cure, and it’s not an overnight process. We start with very low doses and titrate up very slowly in children. It takes time before seeing results if any.

That said, In some children, I’ve been astounded at the benefits I’ve seen in a short period of time in very low doses. But it doesn’t always happen. I have, however, seen benefits such as children becoming more calm and able to follow instructions. 

Calmness can make it much easier for parents, teachers and therapists. It can also make it easier for communication both ways. I’ve seen children become a bit more verbal, sleep increasing and agitation decreasing. Again, remembering that this doesn’t always happen and that this can take time.”

What type of cannabis is normally prescribed for Autism?

If choosing cannabis, normally, a doctor would prescribe cannabis oil for autism in adults and children.

“If treating a child, then I’d usually use a CBD predominant or even CBD only formulation. I might start with a broad spectrum CBD oil so that it wouldn’t have any THC but would have other minor cannabinoids and terpenes, and flavonoids that may create the entourage effect. The goal is that it would work better than a CBD isolate. If we were to use a CBD predominant formulation, it would likely have a THC:CBD ratio of 1:20.

We’d normally have an oil administered under the tongue; If the child doesn’t like the taste, it can be mixed with food. If that’s still not an option, there are chewable tablets (CBD isolate) available. Unfortunately, some kids can smell it even when in the food.

When treating adults, we can be more flexible. In an adult, I might use a 1:1 THC to CBD formulation. I’ve found that sometimes they are useful to support sleep or for agitation or aggression. 

Personally, I like to use an organically grown and as chemical-free as possible product. Organically grown is, in my opinion, very important, particularly for children. Cannabis absorbs whatever is in the soil, almost like a filter. So while our products are tested to a certain level, there can still be foreign residues and individuals on the spectrum can be extremely sensitive to those chemicals. 

What terpenes are beneficial for individuals with Autism?

While specific terpenes in a cannabis product may be beneficial to individuals with Autism, the Australian medical cannabis product market doesn’t have much choice. 

“There also isn’t a huge amount of research into cannabis terpene profiles and benefits for Autism. Much more research needs to be done into what kind of terpene profile is best. The plant’s chemovar or strain can determine the terpene profile.

However, I would think that the most beneficial terpenes would be ones with calming or sedating effects such as myrcene, limonene or linalool. There may also be an important effect from anti-inflammatory terpenes (i.e. beta-caryophyllene)  in Autism to help calm neuroinflammation.

Again, these are all possibilities, but there isn’t enough research to confirm. If we were to find out that these terpenes can help, we could have an exciting area of personalised medicine where we’d create treatments specifically for the patients’ needs.”

Is there a typical dosage of cannabis for treating Autism?

No. Every individual is different and will need something slightly different, and cannabis doesn’t work for everyone. 

Doctors always use the methodology of “start low and go slow.” Patients will always take a very tiny amount of cannabis and then increase slowly over time to prevent side effects and adverse events.

“Particularly with children, I start with the minimal dose possible. Theoretically, you can start with one milligram per kilo of CBD. However, I start much lower than that. Usually, I’ll go with the minimal dose recommended by the producer or even lower. For example, if it’s by drop, I might start a child on one drop either twice or three times a day. Please remember this is not medical advice. It’s simply an example – everyone is a bit different.

Remember, CBD is considered quite safe in humans, and some studies on epilepsy have used doses up to 50mg/kg.”

To give you an idea of how treatment can go, the maximum dose for CBD is 16mg/kg or up to 1g a day, but that’s an extremely high dose. Research has been found one gram to be safe for adults (study one, study two). 

What are the side effects of cannabis for Autism?

Like all drugs, cannabis can have side effects but will vary from patient to patient. To talk about cannabis side effects, we have to look at CBD and THC individually. 

CBD can have side effects that are known to be quite mild. Side effects include:

  • Fatigue
  • Dizziness 
  • Diarrhoea

And, in children on the spectrum, there are cases of increased agitation. With increasing CBD doses, there can be some initial side effects. But they usually go away or can even be prevented with slow titration.

CBD can also interact with other medications. CBD affects the C-450 enzyme in the liver, which processes many medications. Because of this, CBD can change the level of medications found in the blood. It doesn’t necessarily mean that CBD can’t be used with other medications; it just means monitoring is necessary.

THC can also have side effects. Side effects of THC include:

  • Cognitive and psychotropic effects
  • Increased heart rate
  • Coordination problems
  • Dry mouth
  • Red eyes
  • Slower reaction times
  • Memory loss
  • Anxiety

“As mentioned, we do not know what effects THC has on the developing brain with children. That’s why we are cautious when using THC in children. If we need more THC in children, we’ll usually work with a specialist, like a paediatrician or a child psychiatrist.

THC, however, is very safe in terms of toxicity. It takes incredibly high doses to reach a toxic level. So, when compared to other medications, it’s very safe in terms of incidental and even planned ingestion for an actual toxin.”

Caveats on long term side effects

All the information we have on the long-term side effects of cannabis comes from recreational use and ‘uncontrolled’ cannabis. We don’t have much information on long-term medicinal consumption. 

The research about cannabis use in minors looks at teenagers, often smoking high THC flower. And at high levels, far more than would be used in most medical scenarios, that could cause decreased motivation, effects on memory and cognition and addiction. 

“There is some association of increased incidence of schizophrenia in high THC consumption in a younger population. However, there is debate about whether there is evidence of causation.” (Studies covering THC and schizophrenia – study one, study two)

There are also some very, very small longitudinal studies on children with epilepsy. These studies looked at children receiving CBD isolates. These studies suggested high tolerability and safety of CBD in children. 

What are the traditional treatments for Autism?

First-line interventions are usually psychological or behavioural training. The main training is called Applied Behavioural Analysis (ABA). Please be aware that not all ABA therapy is alike, you can learn more about ABA therapy from the Raising Children Network.

Next is medication. There are no medications that cure Autism; all medications aim to treat symptoms. 

Normally doctors will prescribe anxiolytic or antidepressant medication for the treatment of anxiety-related symptoms. These are medications such as SSRIs (i.e. Fluoxetine or Citalopram). To treat agitation or aggression, a doctor might use anti-psychotic medications such as Risperdal, Aripiprazole, Clozapine or Haloperidol. 

If an individual is not sleeping, then a doctor might recommend melatonin or clonidine. If an individual on the spectrum is showing ADHD type behaviours, a doctor might prescribe medication such as Ritalin.

What are some of the side effects of traditional Autism treatments?

Unfortunately, traditional medications for individuals with Autism can have quite significant side effects. 

Anti-psychotic medication such as Risperidone, for example, can cause increased appetite, dizziness, drooling, drowsiness, and fatigue. Aripiprazole can cause weight gain, vomiting and increase appetite and cause fever or upper respiratory tract infections. Haloperidol can cause dyskinesia, abnormal pattern of movement. SSRIs and antidepressants can cause increased energy and impulsivity. They can decrease concentration, cause diarrhoea and insomnia. Ritalin can cause increased irritability. 

“So, these drugs can have the opposite effect that you would expect from them. Instead of being calm, individuals can become more agitated or unwell, which can be quite distressing for both the patient and carer.

What does the research say about cannabis and Autism?

“So, in general, the research is quite encouraging. There is a lack of double-blind, randomised controlled trials. However, one has already been completed, and one is currently underway. 

One of the most recent studies was done by Dr Darryl Effron at the Murdoch Children’s Research Institute. While small, the study showed significant positive effects from a purified CBD formulation. So that was very encouraging.

Another double-blind, randomised placebo-controlled trial showed an improvement in symptoms to the children treated by cannabis. Interestingly, in this study published in 2021, there was no difference between a full-plant extract to their isolated molecules. 

A couple of other observational studies (study one, study two) showed improvements in children with a very mild side effect profile. It’s also important to note that most of the studies used a 1:20 THC:CBD formulation, so it’s not just CBD. 

And as a reminder, cannabis is not a magical cure and doesn’t work for everyone. But, even subtle improvement in aggression, agitation and anxiety can be really life-changing. So as a whole, the research that’s been done is quite encouraging.



dr orit holtzman bio photo honahlee
Dr Orit Holtzman

Dr Orit Holtzman is the Chief Medical Officer of Compass Lifestyle Clinics. She practices functional and cannabinoid medicine with the goal of helping patients live the best life they can.

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Tom Brown

Tom is a co-founder of honahlee, startup junkie, a cannabis enthusiast and a digital marketer. His interest in cannabis began as a teenager growing up in New York. Tom loves to trawl through cannabis research, documenting cannabis truths and myths. He started honahlee to help reduce the stigma around cannabis in Australia by educating people about the many uses of the plant.


The team at honahlee are not doctors and are not providing medical advice. Neither Dr Orit Holtzman nor the honahlee team are recommending the use of marijuana (cannabis) for medical or adult use purposes. Cannabis does not work for everyone and may have negative side effects. In Australia, medical marijuana (cannabis) is regulated by the TGA. If you think cannabis is right for you, please consult with your doctor or specialist.