The use of cannabidiol as adjunctive therapy in adult patients with drug-resistant epilepsy: a systematic review and meta-analysis.

BACKGROUND

Highly purified cannabidiol (CBD), recently approved for various neurological disorders, is explored as a potential therapeutic avenue for drug-resistant epilepsy (DRE) among adult people with epilepsy (PWE) in this systematic review and meta-analysis.

OBJECTIVES

To conduct an extensive literature review and meta-analysis of CBD use for DRE in adult PWE.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES AND METHODS

We conducted a systematic review of the literature according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and two electronic resources; we searched Ovid MEDLINE and Scopus using appropriate keywords until August 2023. Data were presented as standardized mean difference (SMD) and odds ratio with confidence interval (CI) via random effect. We appraised the risk of bias of the included studies using the Joanna Briggs Institute critical appraisal tool while their strength of evidence with the Oxford Centre for Evidence-Based Medicine (OCEBM) and Grading of Recommendations Assessment Development and Education (GRADE) Levels of Evidence.

RESULTS

We identified 16 studies, 3 of which were randomized controlled trials and 3 prospective cohort studies, while the rest were expanded access programs, deriving a total of 668 participants receiving CBD for seizure control. CBD was used concomitantly with antiseizure medications in all studies. There was a statistically significant seizure reduction in the group receiving CBD therapy compared to the placebo group (SMD: -1.50, 95% CI (-3.47, 0.47),  < 0.01).

CONCLUSION

The evidence on CBD use in adult patients with DRE demonstrates a moderate level of certainty according to GRADE level and OCEBM level 2. Further prospective studies involving multiple centers are encouraged to study both the efficacy and safety of CBD in adult patients with DRE.

TRIAL REGISTRATION

International Prospective Register of Systematic Reviews (PROSPERO) 2023 CRD42023449955.