Alcohol Blackout: What Is It and Why Does It Happen?

You may have heard people talking about a night out with friends where they drank a lot and "blacked out." In everyday conversations about partying or celebrating, it's not something you'd necessarily ask people to clarify: "What do you mean, you blacked out?" But the reality is that blacking out can signal a problematic relationship with alcohol, as well as pose serious health risks.

Waking up after a night of drinking and realizing you cannot remember hours of what happened can be frightening. Many people dismiss alcohol blackouts as "just drinking too much," but they are actually a sign that alcohol temporarily disrupted your brain's ability to form new memories. While a single blackout does not necessarily mean someone has alcohol use disorder, repeated blackouts are a warning sign that should never be ignored.

In this article, I'll explain what an alcohol blackout is and what happens in the brain and body when it takes place.

What Is An Alcohol-Induced Blackout?

Alcohol blackouts are when someone cannot remember events that happened while they were intoxicated. They occur when the person has drunk excessive amounts of alcohol, and they can last for minutes or hours. A person typically doesn't realize they've had a blackout until the day after drinking, when they try to recall memories, or when others explain events back to them.

There are two types of blackouts: fragmentary blackout and complete amnesia. Fragmentary blackout is characterized by broken memories of events, where the person can remember some things but not completely or chronologically. Complete amnesia is more severe and is characterized by a total inability to remember any events.

A blackout is not the same as passing out, where a person falls asleep or loses consciousness from consuming too much alcohol. During a blackout, a person is awake, but their brain doesn't create new memories.

When Is a Blackout a Medical Emergency?

Blackouts generally don't require medical intervention, however, seek emergency medical attention immediately if the person:

• Cannot be woken up
• Has slow or irregular breathing
• Vomits while unconscious
• Has seizures
• Has blue lips or skin
• Suffers a serious head injury
• Becomes extremely confused or difficult to arouse

What Causes a Blackout?

When a person drinks alcohol to the point of intoxication, they can temporarily block the transfer of memories from short-term to long-term storage in the hippocampus in the brain. The process being blocked is called memory consolidation, and it can happen even while a person maintains skills such as talking.

There's also research that shows specific regions of the brain are selectively vulnerable to the effects of alcohol. For example, alcohol-related blackouts can alter development in brain regions associated with visual memory. They can also cause retrograde memory impairment, where a person experiences blackouts because of gaps in memory consolidation and because of being unable to retrieve memories in long-term storage.

Who Is Susceptible to Blackouts?

Anyone can experience a blackout when drinking alcohol. Around one third of adults who drink alcohol have had a blackout in the past year, while one half of college students have had an alcohol-related blackout.

However, there are environmental and genetic factors that can increase the likelihood of someone having a blackout while drinking.

Environmental factors include:

• Drinking alcohol without eating before
• Drinking quickly
• Binge drinking
• Drinking while taking medications
• Experiencing blackouts in the past

Genetic factors include:

• Having parents who experience blackouts
• Family members with an addiction
• Alcohol-metabolizing genes that change how the body processes alcohol
• Central nervous system and hippocampal sensitivity to high blood alcohol concentrations

Women are more likely to have blackouts than men. This disparity is because, on average, women weigh less than men and have less water in their bodies, so they reach peak blood alcohol concentration faster. In fact, one study found women who consume just one more drink than their usual amount are 13% more likely to blackout.

What Are the Risks of Blacking Out?

Blacking out carries many risks. The immediate one is the increased risk of injury: people who have experienced six or more blackouts are more than 2.5 times more likely to experience an alcohol-related injury.

Blackouts can also increase the risk of poor decision-making and dangerous behavior, such as driving while intoxicated. On a social level, memory impairment can damage relationships.

Longer-term risks are also present. One study revealed that frequent blackouts are significantly related to more memory lapses and more problems with everyday cognitive functioning.

Other studies noted the psychiatric effects of blackouts. Blackouts have been associated with suicidal ideation and suicide attempts, plus can be predictive of major depression among people with an alcohol use disorder (AUD).

Treatment for Alcohol Abuse

Having blackouts from alcohol doesn't automatically mean that a person has an alcohol use disorder, but it can be a sign that something isn't right. AUD can be slow and quiet to manifest — it often starts with small justifications for drinking and easy dismissal of the seriousness of blackouts.

Treatment for alcohol abuse helps people safely withdraw from alcohol and acknowledge any effects that may have developed as a result of misusing alcohol. Professional treatment significantly improves safety and long-term recovery outcomes, particularly for individuals with moderate to severe alcohol dependence.

Treatment spans detox, residential, outpatient, and aftercare programs, the majority of which integrate Medication-Assisted Treatment (MAT) to alleviate severe withdrawal symptoms, along with evidence-based therapies such as Cognitive Behavioral Therapy (CBT) to address the root causes of excessive alcohol use.

Blackouts shouldn't leave anyone trying to recover in the dark. Treatment for alcohol addiction is available and can be life-changing.

Begin Healing at Regain Hope Detox, Burbank, California

If alcohol blackouts are becoming more frequent or are affecting your relationships, work, or safety, you do not have to face it alone. Recovery is possible, and treatment can begin today. Our physician-led team at Regain Hope Detox provides compassionate, evidence-based care to help you regain control of your health and your future.

Our medically supervised programs support you as you recover, providing a calm, alcohol-free space to heal. With our residential program, you stay at our center and receive evidence-based therapies, MAT, and rebuild a healthy sense of yourself.

All our treatment is tailored around you, factoring in your circumstance and medical history. Care is delivered by one of our certified, on-site clinicians, and we monitor you 24/7 to ensure your safety and progress.

We work with both individuals and couples, serving people in Burbank, Los Angeles County, and Southern California. Our care is available in English, Spanish, and Korean.

Hope is within reach. Regain yours today. Contact our admissions team.

FAQs

Can you blackout after only a few drinks?

Yes. Drinking quickly, drinking on an empty stomach, certain medications, body size, and genetics can all contribute.

Do alcohol blackouts cause permanent brain damage?

Occasional blackouts usually do not, but repeated episodes are associated with long-term cognitive impairment.

Is having one blackout a sign of alcoholism?

Not necessarily. However, repeated blackouts are an important warning sign and should be evaluated by a healthcare professional.

Can you recover memories from a blackout?

Sometimes fragments return when the person is reminded by others, but complete blackouts often involve memories that were never stored in the brain.

This article is intended for educational purposes only and should not replace personalized medical advice. If you believe you or someone else is experiencing alcohol poisoning or another medical emergency, call 911 immediately.