A drug-related blackout is a phenomenon caused by the intake of any substance or medication in which short-term and long-term memory creation is impaired, therefore causing 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.
Research on alcohol blackouts was done 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 whether this is true.[1] The negative psychological after effects of heavy alcohol use are worsened in those with anxiety disorders.[2] The same groups may also experience anxiety around their activities during an alcohol-related blackout, as they have no memory of their actions.[citation needed] Impairment of the liver will also allow more alcohol to reach the brain and hasten the individual's blackout.
The term "blackout" can also refer to a complete loss of consciousness, or syncope.[3]