CBD And Autism: New Hope For Challenging Behaviors?

Research has been exploring the use of cannabidiol (CBD), a substance in cannabis that does not cause psychoactive effects, to help children with autism who exhibit difficult behaviors, such as aggression and self-harm. A recent study tested pure CBD (without THC) in boys with moderate to severe autism and found it to be safe, but did not clearly prove that it works better than a placebo. Despite some signs of improvement, the effects may have been influenced by other medications and the placebo effect. In other words, more research is still needed to know if CBD really helps in these cases.

In recent years, cannabis has gained increasing attention for its potential health benefits. People report that it can help them sleep better, reduce anxiety, relieve chronic pain, treat headaches and even help with more serious psychiatric problems.

Within cannabis, there are substances called cannabinoids, the two main ones being THC (which causes psychoactive effects, such as the "high") and CBD, which does not have this intoxicating effect.

Cannabidiol (CBD), specifically, has sparked the interest of researchers because it may have properties that help calm, combat inflammation and even reduce symptoms of psychiatric illnesses, such as anxiety and schizophrenia. One of the current focuses of CBD research is Autism Spectrum Disorder (ASD).

ASD is a neurodevelopmental disorder that affects communication, behavior, and social interactions. Children with autism may exhibit severe and difficult-to-control behaviors, such as aggression, screaming, intense hyperactivity, and even self-harm (self-harm).

This can seriously disrupt their lives and their families' lives, making it difficult for them to go to school or interact with other children.

There are medications that help control these behaviors, but they often cause serious side effects, such as weight gain, diabetes, high blood pressure, and neurological problems. For this reason, many parents are concerned and seek other alternatives.

In light of this, scientists have been investigating whether CBD could be one of these alternatives. Some open studies, that is, without the use of placebo and based mainly on parental reports, have suggested that CBD products (almost always mixed with THC) could improve the behavior of children with autism, reducing irritability and aggression.

However, these studies used different products, with different doses and without strict control, which makes it difficult to know whether the positive effects observed came from CBD, THC or a combination of the two.

Furthermore, since most of these studies did not have a control group or were carried out without “blinding” the participants and researchers (to prevent expectations from influencing the results), the data are not considered sufficient to prove the effectiveness of CBD.

With this in mind, a group of researchers from the University of California San Diego School of Medicine, USA, decided to conduct a more rigorous, placebo-controlled, double-blind scientific study, meaning that neither the parents nor the researchers knew when the child was taking CBD or a placebo.

The study tested the use of a purified version of CBD called Epidiolex®, already approved by the FDA (US health agency) to treat severe epilepsy in children. They focused on autistic boys between the ages of 7 and 14 with extremely difficult-to-manage behaviors, such as aggression and self-harm.

Each participant went through two phases: in one they took CBD for 8 weeks and in the other they took a placebo, with a 4-week break in between. The researchers assessed behaviors before and after each phase, using several standardized tools to measure autism symptoms and repetitive behaviors.

The results showed that there was an improvement in behavior in both groups, both those taking CBD and those taking a placebo. This indicates that the placebo effect was strong (i.e., simply participating in the study and receiving attention may have improved behavior).

Scores on some scales improved only in the placebo group, but this improvement disappeared when the researchers took into account other medications the children were taking.

When the doctors, who were unaware of what each child was taking, gave their clinical impressions, about 2 in 3 boys showed improvement with CBD, while 1 in 3 showed no improvement or had a similar effect with the placebo.

Importantly, CBD had a good safety profile, that is, it was well tolerated and did not cause serious side effects. But despite some cases of improvement, the study was unable to prove that CBD is clearly effective in reducing problematic behaviors in autism, especially when compared with placebo.

The study reinforces the need for more research, with rigorous methodologies, and raises an important question: can behavioral medications that children already take interfere with CBD levels in their blood and affect outcomes?

In short, while there is much hope that CBD can help children with autism, there is still no solid scientific evidence of its effectiveness, especially in its purified, THC-free form.

The study was important because it was the first of its kind to evaluate pure CBD in children with moderate to severe autism, using a reliable methodology. It showed that CBD is safe, but that its true effects still need to be better understood. For now, the use of CBD in children with autism should be done with caution and always under medical supervision.

READ MORE:

Cannabidiol (CBD) Treatment for Severe Problem Behaviors in Autistic Boys: A Randomized Clinical Trial

Doris Trauner, Anya Umlauf, David J. Grelotti, Robert Fitzgerald, Andrew Hannawi, Thomas D. Marcotte, Caitlin Knight, Lauren Smith, Gisselle Paez, Jennifer Crowhurst, Alyson Brown, Raymond T. Suhandynata, Kyle Lund, Marlen Menlyadiev, and Igor Grant  

J Autism Dev Disord. 24 May 2025

https://doi.org/10.1007/s10803-025-06884-y

Abstract: 

Open-label and observational studies suggest cannabidiol (CBD) reduces problematic behaviors in autistic children. No controlled clinical trials have addressed safety, tolerability, and efficacy. We conducted a double-blind, placebo-controlled crossover study of plant-derived CBD (Epidiolex®) to determine safety, tolerability, and behavior effects in autistic boys. Autistic boys with severe behavior problems age 7–14 years were randomized to eight weeks of CBD up to 20 mg/kg/day and eight weeks of placebo separated by a four-week washout. Behavioral assessments were completed before and after each treatment phase. Plasma concentrations of CBD were quantified. Primary outcomes were changes in total score of the Repetitive Behavior Scale-Revised (RBS-R), Child Behavior Checklist (CBCL), and Autism Diagnostic Observation Schedule-2 (ADOS-2). Both groups improved on the RBS-R and CBCL, with no significant difference between groups. ADOS-2 scores improved in placebo group only, but this improvement disappeared when other medications taken by the children were included in the analyses. Blinded clinical impressions showed almost 2/3 of the participants had behavioral improvements with CBD; 1/3 showed either no change or improvement on placebo. A strong placebo effect was observed. CBD had an acceptable safety profile. We did not find CBD to be clearly effective at reducing the broad range of behaviors characterized by the primary outcome measures. There was clinically evident improvement with CBD in 2/3 of participants. A prominent placebo effect demonstrates the importance of placebo control in treatment studies. Medications taken for behavior may reduce blood levels of CBD and may affect outcome measures.