One of alcohol’s most frightening side effects, blackout is very common but little understood. Many confuse blackouts with passing out after a few hours of hard drinking, but the two are completely different.
People who pass out and sleep deeply for minutes or hours usually have some memory of the events leading up to the moment they passed out, even though they may have to be reminded of their activities during that time. A person who experiences a total blackout has absolutely no awareness because the area of the brain responsible for creation of new memories is totally non-functioning throughout the episode.
A person having a blackout can present a significant danger to others by acting impulsively with no restraint, often engaging in bizarre or violent behavior, unprotected sex, quarreling with others, or breaking the law in various ways.
Blackouts: Two Types
There are actually two types of blackouts. A total blackout, also known as en bloc, involves a complete lack of memory during a specific period of time. The onset of a total blackout tends to be abrupt and occurs with no warning.
A total blackout is different than a fragmentary blackout in which a person retains bits and pieces of memory. Fragmentary blackouts , sometimes known as brownouts, are more common than total blackouts.
Total blackouts, which may last hours or even days, are particularly dangerous because the individual may appear absolutely normal, and may hold lengthy conversations with others, drive a car, or carry out other regular activities.
It’s a common misconception that blackouts happen only to heavy drinkers and alcoholics. Researchers have determined in recent years that blackouts can also happen to occasional and moderate drinkers, sometimes nearly every time they drink, while some heavy drinkers rarely or never experience a blackout. However, it appears that severe, long-term alcoholics are more likely to experience blackouts than occasional social drinkers.
Researchers have yet to come up with an explanation why some drinkers have blackouts while others don’t, but there appears to be a genetic component. Women are at higher risk of blacking out than men because they metabolize alcohol at a slower rate. Women also tend to be smaller, frequently drink wine or whiskey instead of beer, and are more likely to skip meals.