How Effective is CBD for Autism? Review of Anecdotal and Scientific Evidence

In the past decade, cannabinoid research has expanded quickly, but only sporadically focused on autism.

A few of these studies show that out of all cannabinoids, CBD has the biggest potential to be a candidate for the treatment of autism spectrum disorder.

And while several clinical studies are underway, current clinical evidence is limited to one study.

Besides scientific research, there's anecdotal evidence showing CBD may help persons with autism.

Today, we will take a look at the anecdotal and scientific evidence concerning the use of CBD for autism.

First, after the summary, we'll start with some anecdotal evidence.

Keep reading!

Table of contents:

CBD for Autism: Anecdotal Evidence

Studies That Looked at the Effects of CBD on Autism

Clinical Trials in Progress that Will Look at the Effectiveness of CBD for Autism

CBD Can Interact with Medication Prescribed for Autism

CBD for Conditions Secondary to Autism

Conclusion

CBD for Autism: Anecdotal Evidence

Ever since hemp-derived CBD has been federally legalized in 2018, more and more reports have surfaced that talk about how effective CBD products can be for people with autism.

In most of these reports, CBD seems to be an effective aid in dealing with the negative effects that are secondary to autism, like aggression, apathy, anxiety, depression, and epilepsy.

On social discussion website Reddit, various users have reported their positive experiences when it comes to using CBD for autism.

For example, Reddit user and parent “Shoonasasi” posted how CBD oil helped their child with autism:

At the beginning of July we started a 1:20 THC/CBD oil. Within 4 days we saw a calmer child. Unsure if we were really seeing results or if our desperation was seeing it for us, we continued, upping the dose slowly over the weeks. We started at 2 drops per day and made our way to 10, upping the dose by 2 drops a week. We didn't have a single screaming tantrum. Turning his PS4 game off to go to bed no longer resulted in stomping and throwing things, and being told to turn out the light and go to bed did not start 45 minutes of kicking the walls as hard as he could.

A different example from Reddit user “TheChronicCrow”:

I've been taking CBD (and smoking cannabis) for pain and I have noticed it also helps my autism. it's really help my meltdowns/shutdowns and anxiety a lot.

If you search for CBD and autism on Reddit, you'll find many of these types of reports.

These anecdotal reports don't prove that CBD can be used for autism. However, they do provide a strong motivation for research to increase in this area.

Next, we'll look at some studies that researched the effects of CBD on autism

Studies That Looked at the Effects of CBD on Autism

Observational study

One 2019 observational study looked at the effects of standardized CBD-enriched cannabis extract (with a CBD to THC ratio of 75:1) on 18 autism patients (1).

The patients received a daily dose of CBD-enriched cannabis extract for at least 9 months in doses that were equal to 4.55 mg/kg/day CBD and 0.06 mg/kg/day THC on average.

They received two doses daily, one in the morning and one in the evening.

All participants received monthly questionnaires from their physicians for 9 months (14 patients) or 6 months (1 patient). 

The questionnaires covered the following topics:

• Attention-Deficit/Hyperactivity Disorder (ADHD);
• Behavioral Disorders ;
• Motor Deficits ;
• Autonomy Deficits ;
• Communication and Social Interaction Deficits;
• Cognitive Deficits;
• Sleep Disorders;
• Seizures.

Three patients had to abort the study because of adverse effects. Important to note here is that these patients were taking multiple other medications that potentially interact with CBD.

So from these 18 patients, 14 patients continued the study for 9 and 1 patient continued the study for 6 months.

Mostly positive outcomes were reported in these 15 patients who continued. Especially when it comes to sleep disorders, seizures, and behavioral crises the positive effects were most significant.

For motor development, communication and social interaction, and cognitive performance, there were also clear noticeable positive effects, although less significant than the earlier mentioned topics.

Placebo-controlled phase 2 proof-of-concept trial

A clinical trial completed in 2018 looked at the effects of two cannabinoid solutions on various measures in children and adolescents with autism spectrum disorder and behavioral problems (2).

150 children and adolescents aged between 5 and 21 years were divided into three groups of 50.

The first group received whole-plant cannabis extract containing CBD and THC in a 20:1 ratio. Whole-plant extract refers to the fact that the extract also contains small amounts of other cannabis-derived cannabinoids, terpenes, and flavonoids.

The second group received purified CBD and THC in the same ratio and dose, without other components of the cannabis plant such as minor cannabinoids, terpenes, and flavonoids.

The third group received a placebo.

The trial duration was 12 weeks, followed by a 4-week pause, and then another 12 weeks.

The cannabinoid medicines were given in oral form and as an add-on to any pre-existing treatment. The doses were equal to 5.5 mg/kg/day CBD, divided into three daily doses.

Improvement of symptoms was measured with both parent and physician questionnaires.

The results were that both cannabinoid medicines significantly improved behavioral problems compared to placebo.

There were differences between the groups in how they responded:

• Out of group 1 that received a CBD-rich whole-plant cannabis extract showed, 49% showed significant improvement in behavioral problems;
• Out of group 2 that received a pure cannabinoid solution of CBD and THC with a ratio of 1:1, 38% showed significant improvement in behavioral problems;
• Out of group 3 that received a placebo, only 21% showed significant improvement in behavioral problems.

It seems CBD is indeed more effective when taken with other naturally occurring hemp-derived compounds, even when they're only present in small concentrations.

The two most reported side effects in the study were somnolence and weight loss, and they were mostly mild in nature.

Clinical Trials in Progress that Will Look at the Effectiveness of CBD for Autism

There are currently various clinical trials in progress that will look at the effects of CBD on autism.

For example:

One clinical trial started in 2020 and will be completed in 2022, will look at the effects of Epidiolex on severe behavioral problems in children with autism (3). Epidiolex is an FDA-approved prescription medicine for epilepsy. It's an oral solution that contains purified CBD.

The study setup is as follows:

• 30 male participants between 7 and 14 years;
• All participants are diagnosed with autism and severe behavior problems.
• The following measures will be conducted: baseline clinical evaluation, neuropsychological, behavioral, cognitive, and language testing, will have a test of brain wave activity (EEG) and a brain MRI scan;
• Parents will complete questionnaires about their children's behavior;
• There will be two periods of 8 weeks where study participants will receive either CBD or a placebo, divided by a 4 week washout period.

Another open-label clinical trial started in 2019 and that will be completed in 2022 as well, will look at the effects of CBD (again Epidiolex) on behavioral problems secondary to autism, with a focus on anxiety and irritability (4).

The study setup is as follows:

• 30 male and female participants with autism spectrum disorder between the ages of 7 and 17 years old;
• The participants receive 98% pure CBD in doses of 3, 6, or 9 mg/kg/day;
• The treatment period is 6 weeks;
• The primary outcome measure is the “Clinical Global Impression Scale -Improvement (CGI-I)”.

There are a few more clinical trials in progress currently, they can be found on https://clinicaltrials.gov/.

CBD Can Interact with Medication Prescribed for Autism

CBD inhibits CYP450 enzymes (5). This group of enzymes has an important role in the metabolism of approximately 60% of clinically prescribed drugs (6).

For example, the only FDA-approved drug for autism currently is Risperidone. Studies have shown that various CYP450 enzymes are involved in the metabolization of Risperidone (7).

If you want to experiment with CBD, always consult your physician first. Especially if you're already using prescription drugs, you can make things worse by using CBD. Combining CBD with prescriptions drugs can lead to unexpected side effects.

CBD for Conditions Secondary to Autism

Autism often goes together with other conditions that are in some way related to autism. Some of them are behavioral in nature, others are mood-related, and again others are neurological.

For some of these conditions, studies have shown that CBD may be helpful.

Anxiety

Anxiety disorders are prevalent in children with ASD, and CBD has a track record of reducing anxiety in those with autism as well as other people who suffer from it. Social anxiety disorder (SAD) is common in those with autism; the results from a study from 2010 found that CBD reduced social anxiety in the participants (8). This was linked to the effects that CBD had on brain activity in the limbic and paralimbic areas.

Another report from 2015 that analyzed previous studies concluded that they strongly supported CBD as a treatment for anxiety disorders that included: generalized anxiety disorder, social anxiety disorder, obsessive-compulsive disorder, and panic disorder (9), which are often experienced by those with autism. 

CBD's reduction of anxiety is also linked with better sleep.

Aggression

Some children with autism have more aggressive outbursts than average the average child. The anecdotal evidence suggests that CBD has a calming effect on autistic children. But there are also animals studies that found CBD can reduce aggression (10). This effect is possibly related to CBD's interaction with 5-HT1A receptors.

Depression

Depression is a common comorbidity in people with autism. Alongside other ASD symptoms, such as anxiety and mood disorders, the issue can easily be compounded. Tests on rodents have shown that CBD has anti-depressant qualities as well as is fast-acting (11). It was also noted that because CBD doesn't directly activate the endocannabinoid receptors in the brain, it is less likely to become addictive.

Epilepsy & Seizures

Experts believe that there is a strong link between epilepsy and autism. Studies show that 30% of autistic children have epilepsy (12). CBD  works well as an anticonvulsant (13), helping those with autism manage epilepsy and seizures.

Conclusion:

While there's currently only limited scientific evidence supporting CBD as a treatment for autism, the few studies that have been done look promising. There are currently at least 5 clinical trials in progress that will look at the effectiveness of CBD on autism.

If you or your child is suffering from autism, don't go on a path of self-medication. Consult with your physician before you give CBD products a try. CBD can potentially interact with many prescription medicines, therefore it's extremely important to consult your physician before you try CBD for any medical condition, including autism.

What's Next…

Go  to our CBD Hub to learn more about CBD-related topics.

Scientific References:

1. Fleury-Teixeira, P., Caixeta, F. V., Ramires Da Silva, L. C., Brasil-Neto, J. P., & Malcher-Lopes, R. (2019). Effects of CBD-Enriched Cannabis sativa Extract on Autism Spectrum Disorder Symptoms: An Observational Study of 18 Participants Undergoing Compassionate Use. Frontiers in Neurology, 10. Published. https://doi.org/10.3389/fneur.2019.01145
2. Aran, A., Harel, M., Cassuto, H., Polyansky, L., Schnapp, A., Wattad, N., . . . Castellanos, F. X. (2021). Cannabinoid treatment for autism: a proof-of-concept randomized trial. Molecular Autism, 12(1). https://doi.org/10.1186/s13229-021-00420-2
3. Trial of Cannabidiol to Treat Severe Behavior Problems in Children With Autism – Full Text View – ClinicalTrials.gov. (2020). Retrieved from https://clinicaltrials.gov/ct2/show/NCT04517799
4. Cannabidiol for ASD Open Trial – Full Text View – ClinicalTrials.gov. (2019). Retrieved from https://clinicaltrials.gov/ct2/show/NCT03900923
5. Zendulka, O., Dovrtělová, G., Nosková, K., Turjap, M., ŠUlcová, A., Hanuš, L., & Juřica, J. (2016). Cannabinoids and Cytochrome P450 Interactions. Current Drug Metabolism, 17(3), 206–226. https://doi.org/10.2174/1389200217666151210142051
6. Zanger, U. M., & Schwab, M. (2013). Cytochrome P450 enzymes in drug metabolism: Regulation of gene expression, enzyme activities, and impact of genetic variation. Pharmacology & Therapeutics, 138(1), 103–141. https://doi.org/10.1016/j.pharmthera.2012.12.007
7. Berecz, R., Dorado, P., Rubia, A., Caceres, M., Degrell, I., & LLerena, A. (2004). The Role of Cytochrome P450 Enzymes in the Metabolism of Risperidone and Its Clinical Relevance for Drug Interactions. Current Drug Targets, 5(6), 573–579. https://doi.org/10.2174/1389450043345263
8. Crippa, J. A. S., Derenusson, G. N., Ferrari, T. B., Wichert-Ana, L., Duran, F. L., Martin-Santos, R., . . . Hallak, J. E. C. (2010). Neural basis of anxiolytic effects of cannabidiol (CBD) in generalized social anxiety disorder: a preliminary report. Journal of Psychopharmacology, 25(1), 121–130. https://doi.org/10.1177/0269881110379283
9. Blessing, E. M., Steenkamp, M. M., Manzanares, J., & Marmar, C. R. (2015). Cannabidiol as a Potential Treatment for Anxiety Disorders. Neurotherapeutics, 12(4), 825–836. https://doi.org/10.1007/s13311-015-0387-1
10. Hartmann, A., Lisboa, S. F., Sonego, A. B., Coutinho, D., Gomes, F. V., & Guimarães, F. S. (2019). Cannabidiol attenuates aggressive behavior induced by social isolation in mice: Involvement of 5-HT1A and CB1 receptors. Progress in Neuro-Psychopharmacology and Biological Psychiatry, 94, 109637. https://doi.org/10.1016/j.pnpbp.2019.109637
11. Zanelati, T., Biojone, C., Moreira, F., Guimarães, F., & Joca, S. (2009). Antidepressant-like effects of cannabidiol in mice: possible involvement of 5-HT1A receptors. British Journal of Pharmacology, 159(1), 122–128. https://doi.org/10.1111/j.1476-5381.2009.00521.x
12. Tuchman, R., Cuccaro, M., & Alessandri, M. (2010). Autism and epilepsy: Historical perspective. Brain and Development, 32(9), 709–718. https://doi.org/10.1016/j.braindev.2010.04.008
13. Devinsky, O., Cilio, M. R., Cross, H., Fernandez-Ruiz, J., French, J., Hill, C., . . . Friedman, D. (2014). Cannabidiol: Pharmacology and potential therapeutic role in epilepsy and other neuropsychiatric disorders. Epilepsia, 55(6), 791–802. https://doi.org/10.1111/epi.12631