New Study Finds CBD Improved Autism Symptoms in Children

A newly published clinical trial is putting CBD and autism back in the spotlight, and this one is worth paying attention to.

Researchers studying children and adolescents with moderate-to-severe autism found that those receiving a CBD-rich, full-spectrum cannabis extract experienced significant improvements across multiple areas, including communication, social functioning, repetitive behaviors, anxiety, mood and everyday living skills.

And this wasn’t simply a caregiver survey or collection of anecdotal reports.

It was a randomized, double-blind, placebo-controlled Phase II/III clinical trial, one of the strongest types of studies researchers can use to determine whether a treatment is actually making a difference.

The study, called The Harmony Study, was published in Neurotherapeutics in August 2026.

What Did the Study Look At?

Researchers studied 54 children and adolescents diagnosed with Level II or Level III Autism Spectrum Disorder.

Participants were randomly assigned to receive either a placebo or a cannabinoid-rich full-spectrum extract called NTI164 for eight weeks.

NTI164 contains multiple naturally occurring compounds from the cannabis plant and less than 0.3% THC.

The dose was gradually increased up to 20 mg per kilogram of body weight per day.

Throughout the trial, both clinicians and caregivers evaluated changes in the children’s symptoms using several standardized autism, behavior, anxiety and quality-of-life assessments.

At the end of the double-blind portion of the study, participants who had originally received the placebo were also given the opportunity to use NTI164 during an additional eight-week open-label period.

What Did Researchers Find?

The results were pretty remarkable.

Compared with the placebo group, children receiving NTI164 showed statistically significant improvements in several different areas.

Communication and Daily Living Skills

Researchers reported improvements in adaptive functioning, including:

• communication
• daily living skills
• socialization

These are important because they go beyond simply looking at whether a child appeared calmer or less agitated.

Researchers were evaluating changes in how participants communicated, interacted and functioned in their everyday lives.

Social Interaction and Repetitive Behaviors

Participants also showed improvements on assessments measuring social responsiveness.

Researchers reported changes in areas including:

• social awareness
• social cognition
• social communication
• social motivation
• restricted interests
• repetitive behaviors

The study authors ultimately reported significant improvements in both core and associated symptoms of autism compared with placebo.

Anxiety, Mood and Compulsive Behaviors

Another interesting part of the study involved emotional and behavioral symptoms.

Children receiving NTI164 showed improvements in measures involving:

• general anxiety
• depressed mood
• social avoidance
• compulsive behaviors

A separate autism-specific anxiety assessment also found improvements in several types of anxiety, including anxious arousal, uncertainty and separation anxiety.

Families Noticed a Difference Too

The changes weren’t limited to clinical assessments.

Caregivers also reported improvements in their children’s symptoms and in their families’ overall experiences and quality of life.

Researchers evaluated things like family life, the experience of parenting a child with autism, child development, social relationships and overall family experience.

The NTI164 group showed significant improvement compared with placebo.

And there was another interesting piece of the study.

When children who had originally been receiving the placebo switched to NTI164 during the second portion of the trial, researchers reported similar improvements to those seen in the original treatment group.

That adds another layer to the findings.

What About Sleep?

One area that did not show a significant overall improvement was sleep.

Researchers evaluated several different sleep-related issues, but NTI164 did not significantly improve overall sleep compared with placebo.

That may not be the headline-grabbing part of the study, but it’s worth mentioning because it gives a more complete picture of what researchers actually found.

Why This Study Is Different

There has been interest in CBD and autism for years.

Parents have shared experiences. Doctors and researchers have asked questions. Smaller studies have suggested cannabinoids may have potential.

But randomized, placebo-controlled human trials carry a different level of weight.

In this trial, neither the participants nor the researchers evaluating them knew who was receiving the active extract and who was receiving the placebo during the first eight weeks.

That makes it much harder for expectations alone to explain the results.

And the improvements weren’t limited to one measurement.

Researchers saw changes across multiple standardized assessments, with both clinicians and caregivers reporting benefits.

The study authors described NTI164 as having an excellent safety profile during the trial and concluded that the results support continued clinical development of the extract for autism.

Why Researchers Are Looking at Cannabinoids and Autism

One of the reasons cannabis compounds continue to attract scientific interest is the body’s endocannabinoid system.

The endocannabinoid system is a network of receptors, signaling molecules and enzymes involved in helping regulate numerous processes throughout the body, including mood, stress response, sleep, immune activity and nervous-system function.

Cannabinoids such as CBD can interact with this system and with a number of other biological pathways.

Researchers are still working to understand exactly how those interactions may relate to autism, but studies like this are helping move that conversation from theory and anecdotal reports into controlled clinical research.

The Bigger Picture

For years, much of the conversation around CBD has moved faster than the research.

People were using cannabinoids long before scientists had answers for exactly why they might be experiencing certain effects.

Now we’re beginning to see more sophisticated human research catch up.

And that’s what makes studies like this so exciting.

This wasn’t research looking only at irritability or agitation.

Researchers reported improvements in communication, daily living skills, social functioning, repetitive behaviors, anxiety, mood and overall clinical severity.

For families affected by autism, those are meaningful areas of everyday life.

It doesn’t mean scientists have all the answers.

But it does mean researchers now have another controlled human study showing that cannabinoids deserve continued investigation.

And considering how much we still have to learn about the cannabis plant and the endocannabinoid system, that matters.

We’ve been following cannabinoid research since Source began in 2014, and studies like this are exactly why we continue to pay attention.

The science keeps evolving.

And we’re excited to see where it goes next.

Read the Study

NTI164, a novel medicinal cannabis extract, improves core symptoms of autism spectrum disorder: Results from a double-blind, randomised, controlled trial (The Harmony study)

Published August 6, 2026 in Neurotherapeutics.

The study included 54 pediatric participants with Level II or III autism and compared NTI164 with placebo during an eight-week randomized, double-blind phase.

This article is intended for educational purposes and is not medical advice.