Marijuana-based treatment for refractory epilepsy shows promise in surveys, case series, and clinical trials. However, literature on their EEG effects is sparse. Our objective is to analyze the effect of marijuana on EEG in a 24-year-old patient with idiopathic generalized epilepsy treated with cannabis. We blindly reviewed 3 long-term EEGs—a 24-hour study while only on antiepileptic drugs, a 72-hour EEG with Cannabis indica smoked on days 1 and 3 in addition to antiepileptic drugs, and a 48-hour EEG with combination C indica/sativa smoked on day 1 plus antiepileptic drugs. Generalized spike–wave discharges and diffuse paroxysmal fast activity were categorized as interictal and ictal, based on duration of less than 10 seconds or greater, respectively. Data from three studies concatenated into contiguous time series, with usage of marijuana modeled as time-dependent discrete variable while interictal and ictal events constituted dependent variables. Analysis of variance as initial test for significance followed by time series analysis using Generalized Autoregressive Conditional Heteroscedasticity model was performed. Statistical significance for lower interictal events (analysis of variance P = 0.001) was seen during C indica use, but not for C indica/sativa mixture (P = 0.629) or ictal events (P = 0.087). However, time series analysis revealed a significant inverse correlation between marijuana use, with interictal (P < 0.0004) and ictal (P = 0.002) event rates. Using a novel approach to EEG data, we demonstrate a decrease in interictal and ictal electrographic events during marijuana use. Larger samples of patients and EEG, with standardized cannabinoid formulation and dosing, are needed to validate our findings.
*Department of Neurology, School of Medicine, Wayne State University, Detroit, Michigan, U.S.A.; and
†Comprehensive Epilepsy Program, Wayne State University and Detroit Medical Center, Detroit, Michigan, U.S.A.
Address correspondence and reprint requests to Aashit K. Shah, MD, 4201 St Antoine, UHC-8D, Detroit, MI 48201, U.S.A.; e-mail: firstname.lastname@example.org.
Supported by Department of Neurology, Wayne State University.
Presented as a poster at the 68th Annual Meeting of the American Academy of Neurology in Vancouver, BC, Canada, April 15 to 21, 2016.
S. Sivakumar, D. Zutshi, N. Seraji-Bozorgzad, and A. K. Shah contributed toward concept, design, preparation, and final revisions of the manuscript. N. Seraji-Bozorgzad additionally contributed toward data analysis.
The authors have no conflicts of interest to disclose.