Drunk Last Night and Can't Remember? Understand Blackouts and Learn What Causes Alcohol Related Memory Loss

What are alcohol blackouts?

Alcohol blackouts are periods of lost memory during times of alcohol intoxication. Although the terms blacking out and passing out are often interchanged and confused, passing out actually refers to a loss of consciousness, while people who later blackout on memories were fully conscious and often carried out complex events during the time of their memory blackout.

You can't blackout on memories formed while unconscious…there aren’t any to miss!

No one would know to look at an intoxicated person during a time of memory blackout that he or she was in fact in a memory blackout.

Fragmentary and Complete Blackouts

There are 2 types of alcohol induced blackouts – fragmentary and total. People who have experienced a fragmentary blackout may not recall the events of a period of intoxication until they are reminded or cued about them.

• "Remember jumping into the pool last night with your clothes on?"
• "Oh my, I'm starting to remember that now…I can’t believe I did that!"

People who have experienced a total blackout will not remember, even with memory cues, any of the events that occurred during the period of the memory blackout.

• "Remember jumping into the pool with your clothes on?"
• "What pool?"

Blackouts can last for hours or even days. Memory blackouts do not affect memories formed prior to the onset of drunkenness.

Why Does Alcohol Cause Blackouts?

Alcohol is a systematic drug that affects nearly all systems of the brain. The hippocampus, a primary area of memory formation and retrieval, is no exception.

What seems to happen is that alcohol disrupts the brain's ability to consolidate short term memories and process them into long term memories.

We have 3 types of memory.

1. Process or immediate memory
2. Short term memory
3. Long term memory

Process memory lasts only a few seconds, and allows us to perform daily tasks with ease.

Short term memories are slightly more significant, and are stored in the brain for a few minutes.

Short term memories that are very significant, and that are "practiced or thought about quite a lot" are moved into long term storage.

Alcohol seems to block the brain's ability to take salient short term memories and move them into long term storage.

What this means is that since short term memory storage is unaffected, an intoxicated person can maintain a conversation as per normal (Where the flow of the conversation rarely demands that you recall facts for more than a few minutes) but if asked to recall events of an hour before, or the night before, the intoxicated person would have much more trouble.

Is the Occurrence of Blackouts a Sign of Alcoholism?

Much popular literature holds that alcohol blackouts are a warning sign of alcoholism. This is false.

While blackouts are a warning sign of binge drinking, there is no evidence that people who experience blackouts are at any increased risk to develop an alcohol addiction.

The mistaken belief that blackouts cause alcoholism seems to originate out of early research on blackouts that was performed using subjects from AA meetings. Since most AA members reported having had blackouts, it was concluded falsely that blackouts were a sign of alcoholism (Sort or like…since almost all AA members wear shoes – wearing shoes must be a sign of alcoholism!)

What Influences the Occurrence of Blackouts?

Blackouts, like memory in general, are a very poorly understood phenomenon. Research indicates that genetic variables influence the experience (Some people who drink at alcoholic levels never seem to experience blackouts) and the speed of onset of intoxication also seems to influence the occurrence.

The faster you drink, and the faster your blood alcohol level rises, the more likely you are to experience a blackout.