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Alcohol and blackouts

A blackout is different to passing out.

People who experience blackouts usually drink too much, too quickly. This causes your blood alcohol levels to rise very quickly.

A blackout puts you at risk of engaging in dangerous behaviours.

During a blackout, you are fully conscious. You can chat, laugh and may seem quite alert. But later, you may not be able to remember any details of the event.

How blackouts happen

Blackouts happen when you are drunk. During a blackout you temporarily lose the ability to create and store new memories.

This can mean you have no memory of both the good things and bad things which happen while you're drunk. There may be no memory of the big concert which you looked forward to for months, or of the aggressive behaviour you showed towards staff in the takeaway.

This happens because of the way alcohol disrupts the memory centre of the brain.

The memory centre is called the hippocampus. It stores and organises memories so that you can remember things at a later point. When you drink too much or too quickly, this process does not happen like it usually does.

The rate at which your brain stores information can begin to slow even after 1 or 2 drinks.

Types of blackout

There are two types of blackouts:

  • en bloc (total blackout)
  • fragmentary (partial blackout)

En bloc blackout

An en bloc blackout is when you are unable to remember any information for large portions of the day or night.

Fragmentary blackout

A fragmentary blackout is a partial loss of memory after drinking. You may remember bits and pieces when you are reminded.

Reduce your risk of blacking out

Reduce the risk by:

  • drinking within the weekly low-risk guidelines
  • avoid drinking too quickly - sip rather than gulp
  • alternate alcoholic drinks with non-alcoholic drinks
  • eat up - never drink on an empty stomach
  • stay safe - avoid drinking in unfamiliar situations
  • plan ahead how you are getting home

If you are worried about your alcohol use, take our alcohol test to find out what type of drinker you are.

Non-urgent advice: Get help with problem alcohol use

Freephone 1800 459 459 for confidential advice

Page last reviewed: 23 August 2022
Next review due: 23 August 2025