Abstracts

Despite the fact that there is little clinical evidence to support the medical use of marijuana, there is a tremendous amount of interest in the general population in its use for the treatment of a variety of medical condition including epilepsy. A recent survey of the general population reported that 8.9% of respondents had used marijuana in the last year, with 1.9% reporting use for medical reasons. The purpose of this study was to determine the prevalence of and reasons for marijuana use in patients with epilepsy.
Adult patients from the University of Alberta Epilepsy Clinic were questioned with a standardized telephone survey about marijuana use. Subject responses were correlated with information from their clinic charts.
Of 123 subjects contacted, 108 consented to participate (response rate of 88%). Marijuana use of the 108 respondents was as follows: 50 (42%) reported having ever used marijuana, 20 (19%) had used in the last year, 15 (14%) reported monthly use, 14 (13%) weekly use and 6 (6%) daily use. Of subjects who had used marijuana in the last year (n=20), 14 (70%) believed that marijuana improved their seizure control and 8 subjects (40%) specifically reported using marijuana for medical reasons. While general population surveys typically demonstrate higher prevalence of marijuana use in young males, no correlation between marijuana use and age or sex was observed. Weekly marijuana use was significantly more common in subjects with increased seizure frequency and in those without any postsecondary education. No significant correlation was observed between marijuana use and: duration of epilepsy, etiology of seizure disorder, number of anticonvulsant medications, history of epilepsy surgery or employment status.
The prevalence of marijuana use of patients in a tertiary epilepsy clinic is over twice that observed in the general population. The difference in the demographics of marijuana users in epilepsy patients and the general population, suggests that marijuana use in patients with epilepsy is different from that in the general population (being used for medical as opposed to recreational purposes). This idea is further substantiated by the finding that the majority of active users reported improved seizure control with marijuana use. These observations support the need for clinical studies to evaluate the effects of marijuana use on seizure control in epilepsy patients.