Commentary: Alcoholic blackout and allegation of amnesia during criminal acts.

The article by van Oorsouw and colleagues presents interesting survey and experimental data, exploring the question of whether alcohol blackouts occur frequently or are used primarily as an excuse to minimize legal responsibility. The authors concluded that the results of their analysis indicated that blackouts during serious misbehavior are often reported outside the court, but the denial or claim of alcoholic blackout may serve a strategic function for the person who raises the claim. Reports of alcoholic blackouts are well documented in the psychiatric literature. Lishman notes that an alcoholic blackout consists of a dense amnesia for significant events which have occurred during a drinking episode, when at the time outward behavior perhaps seemed not disordered. Usually the gap extends for a period of several hours, but very occasionally, it may cover several days. Goodwin et al. have presented detailed descriptions of the nature of blackouts in 64 subjects. This is one of the earliest research studies of alcoholic blackouts in American psychiatry. One fourth of their patients found themselves in strange places with no recollection of how they got there. The wives of two of these patients reported that they could tell when a blackout was in progress, by their husbands’ glassy stare, belligerent behavior, or repetition of questions that showed that experiences were failing to register. These blackouts were described as en bloc and were distinguished from fragmentary memory losses, in which the subject was unaware that events had been forgotten, until he or she was told about them later. An early investigation by Tarter and Schneider explored the possibility that alcoholics subject to blackouts might have some enduring impairment of memory when sober. Their results were uniformly negative for that question, and, on a wide battery of neuropsychological memory measurements, those with the highest incidence of blackouts performed as well while sober as those in whom blackouts were rare. Goodwin and colleagues demonstrated further that volunteers trained and tested while under the effects of alcohol demonstrated some reproducible findings. During periods of moderate intoxication, registration was substantially normal, but short-term memory was considerably impaired. More severe intoxication caused a significant decrease in registration and a more profound diminishment in shortterm memory. Subjects demonstrated poor ability to recall the events of the preceding day on days following moderate intoxication, and decreased recall was even more pronounced on days following severe intoxication. The diminishment of memory was also related to the duration of intoxication, in that it tended to become worse as the days of the experiment went by. Defects in 24-hour recall were also more frequent and severe. The worse the short-term memory had been, the greater the level of intoxication had been. Conversely, 24-hour recall was always normal in subjects who had shown intact short-term memory the day before. This study demonstrated further marked individual susceptibility to the same blood-alcohol level affecting each subject to a variable extent. Only 6 of the 13 subjects showed blackouts, which were defined as the ability to answer less Dr. Granacher is Clinical Professor of Psychiatry, University of Kentucky College of Medicine and President of the Lexington Forensic Institute, Lexington, KY. Address correspondence to: Robert P. Granacher, Jr, MD, 1401 Harrodsburg Rd., Saint Joseph Office Park, Lexington, KY 40504. E-mail: [email protected]