Blackout

One Night, Gone Forever: What Blackouts Do to Your Brain

Many people think of an alcohol blackout as simply “forgetting parts of the night.” But blackouts are actually a sign of something much more serious: alcohol is shutting down the brain’s ability to make new memories.

What is an Alcohol Blackout?

Ever woken up the day after a “big night” and can’t remember what you’ve done the night before??? Or maybe you’ve had “a few drinks” at home to help wind down the day or get yourself to sleep, with no recollection the next morning. “What did I say?” “How did I get into my bed?” “Who was I with?” Then later you see messages you’ve sent; posts you’ve made on social media; things you’ve purchased; phone calls you’ve made…. All with little or no memory of doing so.

During a blackout, you might look and act kind of normal. You can talk, walk, dance, or even drive, or eat a meal — but your brain isn’t recording what’s happening. This is because alcohol affects the hippocampus, the part of the brain that helps store new memories.

There are two main types of blackouts:

• En bloc blackout: a complete memory gap, where no amount of prompting will bring the memory back.

• Fragmentary blackout: patchy recall, where you might remember some details if someone reminds you.

In both cases, it’s not that the memories are “lost” — they were never made in the first place. [1][4] This can be a scary experience. There are of course major risks people can place themselves in both out or at home, and irreversible consequences of some behaviours that they may have engaged in whilst experiencing a blackout.

How Do Blackouts Affect Thinking and Memory?

Blackouts don’t just affect memory during the event itself. They can have roll on effects into the next day and even weeks and years after :

• The next day: Even when sober, people often find their recall and thinking are foggy. [3] Information might be fragmented or there may be no memory at all.

• Everyday life: Frequent blackouts are linked to ongoing problems with memory, concentration, and decision-making. People often report feeling mentally “slower” or less sharp. [2] This can start to affect your daily functioning, not only at work but at home as well.

• Coordination and reaction time: Regular blackout drinkers may also struggle with processing visual information quickly — which can affect activities like driving. [4][5]

Do Repeated Blackouts Cause Lasting Damage?

Yes. While a single blackout is concerning, repeated episodes can have long-term effects on the brain:

• Memory loss that sticks: Research shows that frequent blackout drinkers report more memory lapses over time, even outside of drinking episodes. [1][2]

• Learning difficulties: In young people especially, blackouts can slow the development of memory and problem-solving skills. [2] This can affecting your ability to analyse a situation and come up with the most appropriate responses.

• Changes in brain structure: Long-term heavy drinking damages areas of the brain involved in memory and learning, increasing the risk of alcohol-related dementia. [3][4]

Why It Matters

Blackouts aren’t just “funny stories” about a wild night, or something that just happens “every now and again when I have a few too many.” They’re warning signs that alcohol is seriously interfering with brain function. If blackouts are happening often, it may point to risky or harmful drinking patterns.

Recognising blackouts for what they are — evidence of brain harm — is an important step in making informed choices about alcohol use and protecting long-term cognitive health.

If you or someone you know experiencing blackouts or you are thinking that your drinking or drug use may be problematic, reach out for support. If you would like to talk to a professional make an appointment with one of our Addiction Specialists at AACE Metrix or contact the Alcohol and Drug Support Line in your area to discuss the options available to you.

References

1. Lee H, Roh S, Kim DJ. Alcohol-Induced Blackout. Int J Environ Res Public Health. 2009;6(11):2783-92. doi:10.3390/ijerph6112783.

2. Linden-Carmichael AN, Mogle J, Miller SE. Associations Between Blackout Drinking and Self-Reported Everyday Cognition Among Young Adults. Addict Behav. 2023;141:107653. doi:10.1016/j.addbeh.2023.107653.

3. Jackson J, Donaldson DI, Dering B. The Morning After the Night Before: Alcohol-Induced Blackouts Impair Next Day Recall in Sober Young Adults. PLoS One. 2021;16(5):e0250827. doi:10.1371/journal.pone.0250827.

4. Hermens DF, Lagopoulos J. Binge Drinking and the Young Brain: A Mini Review of the Neurobiological Underpinnings of Alcohol-Induced Blackout. Front Psychol. 2018;9:12. doi:10.3389/fpsyg.2018.00012.

5. Vetreno RP, Hall JM, Savage LM. Alcohol-Related Amnesia and Dementia: Animal Models Have Revealed the Contributions of Different Etiological Factors on Neuropathology, Neurochemical Dysfunction and Cognitive Impairment. Neurobiol Learn Mem. 2011;96(4):596-608. doi:10.1016/j.nlm.2011.01.003.