Long-term follow-up of children with autism spectrum disorder and severe treatment-resistant behavioral symptoms treated with purified cannabidiol.

This was an observational study — researchers watched what happened rather than assigning treatments. It can show that two things happen together, but it cannot show that one caused the other.

It involved only 20 people. Without random assignment, a group this small makes it especially easy for something other than what was studied to explain the difference researchers saw. Treat this as a very early signal rather than an answer.

The researchers concluded: "Long-term treatment with purified CBD in children with severe ASD was well tolerated and associated with sustained improvement in caregiver-reported outcomes and standardized scales."

This record does not state:

• how long the study ran

This is a plain-language summary of one paper's abstract, not medical advice. Talk to your child's clinician before changing anything.

Journal: Pharmacology, biochemistry, and behavior

Year: 2026

Design: Observational Study

Participants: 20

Age range: 3-18 years

Intervention: cannabidiol (CBD)

Authors: Pablo Sebastián Fortini, Javier J Toibaro, Roberto H Caraballo

BACKGROUND: Autism spectrum disorder (ASD) is a heterogeneous neurodevelopmental condition often associated with severe behavioral disturbances and limited pharmacological treatment options. Cannabidiol (CBD) has emerged as a potential therapeutic option; however, evidence on its long-term effectiveness and safety in children with ASD is scarce. OBJECTIVE: To evaluate the long-term effectiveness and safety of purified CBD as add-on therapy in children with severe ASD and treatment-resistant behavioral symptoms. MATERIAL AND METHODS: We conducted a prospective observational before-and-after study in children and adolescents (3-18 years) with ASD severity levels 2 or 3 and intellectual disability treated with add-on CBD. The primary outcome was change in caregiver-identified symptoms, while secondary outcomes included standardized behavioral scales (Repetitive Behavior Scale-Revised [RBS-R], Vineland Adaptive Behavior Scales-II maladaptive behavior domain, Aberrant Behavior Checklist [ABC], Pediatric Sleep Clinical Global Impressions-Severity, Autism Family Experience Questionnaire, and Parental Stress Scale). Safety and tolerability were assessed through caregiver-reported adverse events. RESULTS: Twenty children were enrolled, of whom 13 completed the long-term follow-up (mean 27.6 ± 1.3 months). Of the caregiver-identified symptoms, improvements observed during the initial short-term study were maintained or further improved during follow-up. Standardized scales showed modest but sustained improvements, particularly in irritability, social withdrawal, and hyperactivity. Mild, transient adverse events, mainly irritability or decreased appetite, did not recur during long-term followup, and concomitant medications were reduced in 40% of patients. CONCLUSION: Long-term treatment with purified CBD in children with severe ASD was well tolerated and associated with sustained improvement in caregiver-reported outcomes and standardized scales.

Pharmacology, biochemistry, and behavior, 2026

PMID 42248366

DOI 10.1016/j.pbb.2026.174220

This record was extracted from the paper's PubMed abstract and metadata. Full-text methods and risk-of-bias details were not reviewed.