Long-term CBD isolate use is effective for childhood focal epilepsy

Treatment-resistant childhood epilepsy can be a devastating condition, and is frequently treatment-resistant. This open label study examined the effectiveness of CBD isolate on kids diagnosed with different types of focal epilepsy. It was published in the journal Epilepsia in July 2025.

An open label study simply means the patients/caregivers knew the product name and brand of the medicine they were taking. The types of diagnosed focal epilepsies included:

  • 24% had TSC (tuberous sclerosis complex)
  • 76% had other focal epilepsies, including:
    • cortical dysplasia (14%)
    • frontal lobe epilepsy (10%)
    • malformation of cortical development (9%)

 

The study had a 4-week baseline period (without CBD) where parents or caregivers recorded all seizures in a diary. 

140 treatment-resistant TSC focal epilepsy patients with a median age of 11.9 years then received an FDA-approved, purified CBD isolate in starting doses of between 2 and 10 mg/kg/day. The dose was then titrated based on results, up to a maximum of 25 to 50 mg/kg/day. 

For reference, 75 pounds of body weight would yield the following daily doses:

  • 2 mg/kg/day would be about 70 mg/day 
  • 10 mg/kg/day would be about 340 mg/day
  • 25 mg/kg/day would be about 850 mg/day
  • 50 mg/kg/day would be about 1.7 grams (1700mg) /day

 

The median final dose was about 25 mg/kg/day, or 850 mg/day for a 75 pound child and 570 mg/day for a 50 pound child. These are not small doses. 850 mg/day would be considered a large dose for adults. However, the CBD was not a full spectrum extract and included no other cannabinoids or active ingredients.

They followed the patients for 144 weeks and measured changes in focal and total seizures.

In general, the average patient experienced a reduction in seizures of over 50%, with some experiencing a reduction of almost 90%. Given that these kids did not respond to traditional treatment, it seems like the CBD isolate was very effective.

Results summary in the authors' words:

CBD treatment was associated with a median reduction from baseline of:

51%–87% in focal seizures and 44%–87% in total seizures in the TSC group

46%–75% and 45%–71% in the non-TSC group

Seizure freedom (100% response rate) was reported in 11%–20% and 5%–14% of patients for focal and total seizures, respectively

Adverse events occurred in 91% of the TSC group and 96% of the non-TSC group.

 

The authors felt the safety profile was consistent for the condition. A summary of the most common adverse events recorded:

  • Diarrhea
  • Convulsion
  • Somnolence

 

Authors' conclusion:

CBD treatment was associated with sustained seizure reduction through 144 weeks, with a consistent safety profile in patients with treatment-resistant focal epilepsies, regardless of epilepsy type.

 

The full text article is here at the Wiley Online Library.

Source:

Patel AD, Szaflarski JP, Lyons PD, Boffa M, Greco T, Saurer TB, Rajasekaran K, Simontacchi KC, Thiele EA. Long-term efficacy and safety of cannabidiol in patients with treatment-resistant focal epilepsies treated in the Expanded Access Program. Epilepsia. 2025 Jul 17. doi: 10.1111/epi.18496. Epub ahead of print. PMID: 40673944.

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