Purpose: The purpose of this research was to analyze and quantify the association between alcohol consumption and epilepsy as an independent disease, in part operationalized by the occurrence of unprovoked seizures, as well as to examine causality.
Methods: Systematic review, meta-analysis.
Results: A strong and consistent association between alcohol consumption and epilepsy/unprovoked seizures was found with an overall relative risk (RR) of 2.19 [95% confidence interval (CI) 1.83-2.63]. There was a dose-response relationship between the amount of alcohol consumed daily and the probability of the onset of epilepsy. Individuals consuming an average of four, six, and eight drinks daily had RRs of 1.81 (95% CI 1.59-2.07), 2.44 (95% CI 2.00-2.97), and 3.27 (95% CI 2.52-4.26), respectively, compared to nondrinkers. Several pathogenic mechanisms for the development of epilepsy in alcohol users were identified. Most of the relevant studies found that a high percentage of alcohol users with epilepsy would qualify for the criteria of alcohol dependence. Data were inconclusive regarding a threshold for the effect of alcohol, but most studies suggest that the effect may only hold for heavy drinking (four and more drinks daily).
Discussion: The relationship between alcohol consumption and epilepsy and unprovoked seizures was quantified and several pathogenic mechanisms were suggested, although none of them has been proven to be the unique causative pathway for epilepsy. Certain limitations underlying this study require further research to clarify the outstanding statistical issues and pathogenesis of epilepsy in heavy drinkers.