Relationship between effects of alcohol on psychomotor performances and blood alcohol concentrations

Ethanol is a social drug and has been generally known to be a CNS depressan t. A large fluctuation of blood alcohol concentration (BAC) is well-known t o occur due to main factors such as the genetic polymorphism of the main al cohol metabolizing enzymes and the effect of blood. Few studies have substa ntially discussed the relationship between impaired CNS activities and BAC. In this study, focusing on the correlation of BAC, we investigated the acu te effects of alcohol intake on cognitive performance in humans by objectiv e evaluation methods consisting of the attention-demanding cognitive tasks. Tasks were administered to ten healthy male volunteers before and after in gesting established amounts of alcohol. With increased BAC, we observed pro longation of reaction time performances and lowering of a coordination perf ormance. From the results, we concluded that cognitive performance deterior ates with an increase of BAC. Additionally, the BAC threshold that causes s ignificant impairment of cognitive performance was estimated to be approxim ately 50 mg/dl (ca. 10 mM).