A blackout is a phenomenon caused by the intake of an alcoholic beverage or other substance in which long term memory creation is impaired or there is a complete inability to recall the past. Blackouts are frequently described as having effects similar to that of anterograde amnesia, in which the subject cannot recall any events after the event that caused amnesia. ‘Blacking out’ is not to be confused with the mutually exclusive act of ‘passing out’, which means loss of consciousness.
Research on alcohol blackouts was begun by E. M. Jellinek in the 1940s. Using data from a survey of Alcoholics Anonymous (AA) members, he came to believe that blackouts would be a good determinant of alcoholism. However, there are conflicting views as to whether this is true. The negative psychological effects of an alcohol-related blackout are often worsened by those who suffer from anxiety disorders.
Various studies have also given rise to proof of links between general alcohol consumption and its effects on memory capacity. These studies have shown in particular, how the innebriated or intoxicated individual makes poorer associations between words and objects than does the sober individual. Later blackout-specific studies have indicated that alcohol specifically impairs the brain’s ability to take short-term memories and experiences and transfer them to long-term memory.
It is a common misconception that blackouts generally occur only in alcoholics; research suggests that individuals who engage in binge drinking, such as many college students, are often at risk as well. In a 2002 survey of college students by researchers at Duke University Medical Center, 40% of those surveyed who had consumed alcohol recently, reported having experienced a blackout within the preceding year.