# Real-world effectiveness of highly purified cannabidiol in epilepsy associated with 15q11.2-q13.1 duplication and deletion syndromes: A multicenter study. > **Author:** Benjamin Caplan, MD (ABFM Board Certified, MA Lic. #240562, NPI: 1962722637) > **Publisher:** CED Clinic (https://cedclinic.com) > **Canonical URL:** https://cedclinic.com/highly-purified-cannabidiol-epilepsy-effectiveness-study/ > **Published:** 2026-04-17T09:05:42-04:00 | **Last Modified / Clinically Audited:** 2026-09-28T10:19:59-04:00 > **Clinical Summary:** Explore the real-world effectiveness of highly purified cannabidiol epilepsy treatment in patients with 15q11.2-q13.1 duplication and deletion syndromes. --- CED Clinical Relevance  #65Notable Clinical Interest  Emerging findings or policy developments worth monitoring closely. 🔬 Evidence Watch  |  CED Clinic EpilepsyCbdPediatrics[Rare Disease](https://cedclinic.com/advancing-rare-neurodegenerative-diseases-research/)[Clinical Study](https://cedclinic.com/cannabis-hyperemesis-syndrome-psychiatric-risk/) Journal Epilepsia open Study Type [Clinical Study](https://cedclinic.com/cannabis-hyperemesis-syndrome-psychiatric-risk/) Population Human participants Why This Matters This study provides crucial real-world evidence for CBD effectiveness in rare genetic epilepsy syndromes where treatment options are severely limited. The 55.7% average seizure reduction and 63.6% responder rate in 15q chromosomal abnormality syndromes helps inform dosing and expectations for this vulnerable population. Clinical Summary This multicenter retrospective study followed 22 patients with 15q11.2-q13.1 duplication or deletion syndromes treated with highly purified CBD for a median of 21 months. Results showed meaningful seizure reductions with 63.6% achieving ≥50% seizure reduction and 18.2% becoming seizure-free. Tonic seizures in duplication syndrome and myoclonic seizures in Angelman syndrome responded particularly well. EEG improvements occurred in nearly half of evaluated patients, with clinical global improvement reported in 72.7% of cases. Dr. Caplan’s Take “These response rates in rare genetic epilepsies are clinically significant and align with what I observe in practice with treatment-resistant epilepsy patients. The seizure-type specific responses provide valuable guidance for managing expectations with families facing these devastating conditions.” Clinical Perspective 🧠 Clinicians should consider CBD as a viable treatment option for patients with 15q chromosomal abnormality syndromes, particularly those with predominant tonic or myoclonic seizures. The multicenter real-world data supports meaningful [quality of life](https://cedclinic.com/cannabis-policy-enforcement-february-26-2026/) improvements beyond just seizure reduction, which is critical when counseling families about treatment goals. 💬 Join the Conversation Have a question about how this applies to your situation? [Ask Dr. Caplan →](https://benjamincaplan.com/ask-dr-caplan) Want to discuss this topic with other patients and caregivers? [Join the forum discussion →](https://cedclinic.com/interact/discussion-forums/) Have thoughts on this? Share it: [𝕏 Share on X](https://twitter.com/intent/tweet?text=Just%20read%20this%20on%20CEDclinic.com%3A%20Real-world%20effectiveness%20of%20highly%20purified%20cannabidiol%20in%20epilepsy%20associated%20w...%20%40drcaplan&url=https%3A//pubmed.ncbi.nlm.nih.gov/41992447/)[in Share on LinkedIn](https://www.linkedin.com/sharing/share-offsite/?url=https%3A//pubmed.ncbi.nlm.nih.gov/41992447/)[🦥 Share on BlueSky](https://bsky.app/intent/compose?text=Just%20read%20this%3A%20Real-world%20effectiveness%20of%20highly%20purified%20cannabidiol%20in%20epilepsy%20associated%20w...%20--%20via%20%40drcaplan.bsky.social%20https%3A//pubmed.ncbi.nlm.nih.gov/41992447/)[📷 Follow on Instagram](https://www.instagram.com/drbenjamincaplan/)[📝 Read more on Substack](https://substack.com/@doctorapproved)[🔔 Subscribe via RSS](https://cedclinic.com/category/cannabis-news/feed/) 📰 Source: [https://pubmed.ncbi.nlm.nih.gov/41992447/](https://pubmed.ncbi.nlm.nih.gov/41992447/) Table of Contents - [FAQ](#FAQ)[How effective is highly purified CBD for seizures in patients with 15q11.2-q13.1 duplication and deletion syndromes?](#How_effective_is_highly_purified_CBD_for_seizures_in_patients_with_15q112-q131_duplication_and_deletion_syndromes) - [Which seizure types respond best to CBD in these genetic syndromes?](#Which_seizure_types_respond_best_to_CBD_in_these_genetic_syndromes) - [What is the typical age and clinical profile of patients who benefit from CBD therapy?](#What_is_the_typical_age_and_clinical_profile_of_patients_who_benefit_from_CBD_therapy) - [Does CBD improve brain wave activity beyond seizure reduction in these patients?](#Does_CBD_improve_brain_wave_activity_beyond_seizure_reduction_in_these_patients) - [What broader clinical improvements can families expect with CBD treatment?](#What_broader_clinical_improvements_can_families_expect_with_CBD_treatment) - [Related](#Related) ## FAQ #### How effective is highly purified CBD for seizures in patients with 15q11.2-q13.1 duplication and deletion syndromes? This multicenter study demonstrated significant seizure reduction with a mean decrease of 55.7% across 22 patients. Notably, 63.6% of patients achieved ≥50% seizure reduction, 40.9% achieved ≥75% reduction, and 18.2% became seizure-free during a median follow-up of 21 months. #### Which seizure types respond best to CBD in these genetic syndromes? Tonic seizures in patients with 15q duplication syndrome and myoclonic seizures in Angelman syndrome patients showed the most notable reductions. This suggests CBD may have particular efficacy for specific seizure types associated with these distinct genetic conditions. #### What is the typical age and clinical profile of patients who benefit from CBD therapy? The median age at CBD initiation was 14.5 years, indicating effectiveness in pediatric and adolescent populations. All patients with 15q duplication syndrome and two Angelman syndrome patients presented with Lennox-Gastaut phenotype, a severe epilepsy syndrome that is typically treatment-resistant. #### Does CBD improve brain wave activity beyond seizure reduction in these patients? Yes, EEG improvement was observed in 7 out of 16 patients evaluated, with marked improvement noted in two patients with 15q duplication syndrome. This suggests CBD may normalize underlying brain electrical activity patterns beyond just reducing clinical seizures. #### What broader clinical improvements can families expect with CBD treatment? Clinical improvement on standardized assessment scales was reported in 72.7% of patients, indicating benefits beyond [seizure control](https://cedclinic.com/portable-eeg-epilepsy-monitoring-seizure-detection-dogs/). The study mentions additional non-seizure improvements, suggesting CBD may enhance overall [quality of life](https://cedclinic.com/cannabis-policy-enforcement-february-26-2026/) and functioning in these complex genetic syndromes. [https://cedclinic.com/contact/](https://cedclinic.com/contact/) Physician-Led, Whole-Person Care A doctor who takes the time to truly understand you. Personal care that starts with listening and is guided by experience and ingenuity. Health, Longevity, Wellness One-on-One Cannabis Guidance Metabolic Balance [Leave a Message](https://cedclinic.com/contact/) [Metabolic Care](https://cedclinic.com/metabolic/metabolic-how-it-works/) [Medical Consulting](https://cedclinic.com/book/) [Cannabis Care](https://cedclinic.com/book/) [https://cedclinic.com/contact/](https://cedclinic.com/contact/) RELATED READING AT CED CLINIC Continue exploring the evidence [Real-world effectiveness of highly purified cannabidiol in epilepsy associated with 15q11.2-q13.1 duplication and deletion syndromes: A multicenter study.](https://cedclinic.com/cbd-treatment-genetic-epilepsy-syndromes-study-results/) Detailed study results on cannabidiol treatment for epilepsy in patients with 15q chromosomal abnormalities. [Read the full study](https://cedclinic.com/cbd-treatment-genetic-epilepsy-syndromes-study-results/) [New Clinical Insights on Cannabis and Patient Outcomes](https://cedclinic.com/new-clinical-insights-on-cannabis-and-patient-outcomes/) Explore recent clinical findings on cannabis and its impact on patient health outcomes. [Discover insights](https://cedclinic.com/new-clinical-insights-on-cannabis-and-patient-outcomes/) [Is CBD Safe for Teens? Risks, Side Effects, and the Law](https://cedclinic.com/is-cbd-safe-for-teens-risks-side-effects-and-the-law/) An overview of CBD safety, [side effects](https://cedclinic.com/cannabis-intoxication-memory-disruption/), and legal considerations for adolescent use. [Learn about CBD safety](https://cedclinic.com/is-cbd-safe-for-teens-risks-side-effects-and-the-law/) ### Related --- ### Verification & Medical Governance - **Lead Clinical Author:** Benjamin Caplan, MD - **Credentials:** Board Certified in Family Medicine (ABFM), Former CMO Canna Care Docs (250,000+ patients supervised), Founder & CMO CED Clinic & CED Foundation, Author of *The Doctor-Approved Cannabis Handbook* (Penguin Random House). - **Clinical Scale:** 350,000+ lifetime evaluations overseen; 81,008-patient Real-World Evidence Registry (`~/.ced_rwe_vault.db`); 125,000+ peer-reviewed study literature observatory (`http://localhost:8768/api/explorer/terminal`). - **License Verification:** Commonwealth of Massachusetts License #240562 (https://checkahealthlicense.mass.gov/). - **NPI Registry:** 1962722637 (https://npiregistry.cms.hhs.gov/provider-view/1962722637). - **Ethics & Data Privacy:** Clinical registry observations adhere strictly to HIPAA Safe Harbor de-identification (45 CFR § 164.514(b)) and criteria for secondary research exemption under 45 CFR § 46.104(d)(4).