Children with Rett Syndrome Experience Symptom Improvement Using Low THC Cannabis Extracts

A recent study investigated the safety and efficacy of cannabis extracts with low tetrahydrocannabinol (THC) and its use with children suffering from Rett syndrome (RTT), a rare genetic disorder that may be connected to loss of speech and motor coordination, seizures, involuntary/repetitive movements, and developmental delays (1,2).

The open-label clinical trial data was published in the Journal of Pediatrics and Child Health (2). NORML (1), reported that “Australian investigators assessed the twice-daily use of cannabis extracts containing CBD and THC in a cohort of 11 girls with RTT.” Participants in the study were then measured using “the Clinical Global Impression-Improvement (CGI-I) Scale, with secondary outcomes measured using the CGI-Severity (CGI-S), RTT Behaviour Questionnaire (RSBQ), RTT-Symptom Index Score (RTT-SIS), RTT-Domain-Specific Concerns-Visual-Analog Scale (RTT-DSC-VAS), Impact of Childhood Neurological Disability/Quality of Life (ICND+QoL), and RTT-Caregiver Burden Inventory (RTT-CBI),” (2). Researchers gathered data from 11 female participants between the ages of 5 to 16 years old from the Rett Syndrome Multidisciplinary Management Clinic at The Children’s Hospital at Westmead, NSW, Australia (2) and had data collected at the beginning of the study and at 12 weeks. Study authors mentioned that all participants were six months post-regression when they were screened in the beginning.

“Oral administration of [cannabis extracts] for 12 weeks was associated with significant improvements in core RTT symptoms, including mental alertness, communication skills, socialization/eye contact, attentiveness, and anxiety,” study researchers found (1). “[Cannabis] administration also demonstrated improvements in key secondary outcomes, such as overall clinical severity, quality of life, and a reduction in caregiver burden.”

Research data collected showed that participants experienced improvement in mood, teeth grinding, and breathing (1,2).

In conclusion, researchers said (1), “The study’s authors concluded: “RTT is associated with a range of complex clinical manifestations. … This Phase I/II study of [plant-derived cannabis extracts] in RTT provides an encouraging foundation for further studies in this population. The improvements observed in clinical outcomes and caregiver burden justify ongoing research and confirm [that cannabis extracts are] a potential adjunct therapy for RTT.”

References

1. Norml. Cannabis extracts improve symptoms in children with Rett syndrome https://norml.org/news/2025/07/10/study-low-thc-cannabis-extracts-improve-symptoms-in-children-with-rett-syndrome/ (accessed Jul 15, 2025).
2. Keating BA, Ogru Y, Duthy TG, et al. Full-Spectrum Medicinal Cannabis Plant Extract 0.08% THC (NTI164) Improves Symptoms of Rett Syndrome: An Open-Label Study. J Paediatr Child Health. Published online June 26, 2025. doi:10.1111/jpc.70122