Blackout Drunk: Signs, Causes, and Dangers of Blackout Drinking

What is a Blackout?

According to the National Institute on Alcohol Abuse and Alcoholism (NIAAA), alcohol-induced blackouts refer to “gaps” in a person’s memory for events that occurred while they were intoxicated.¹

People often confuse “blacking out” with “passing out” (aka syncope), which is a temporary loss of consciousness when someone no longer displays voluntary behaviors. However, an alcohol-related blackout involves losing your memory while you’re still awake and conscious. During a blackout, you can move around, interact with others, and seem fine to those around you. Blackouts are caused by drinking high quantities of alcohol, which leads to an impairment in the way your brain transfers memories from short- to long-term memory.¹

Alcohol-related blackouts come in two different types. If you experience a fragmentary blackout, also known as a “grayout” or “brownout,” you may have gaps in your memory combined with some recollection of events. Whereas, a total blackout involves no recollection of events because memories of what happened never form, and if they do, you cannot access them. People with this type of blackout, also called an “en bloc” blackout, have amnesia that can last for many hours.¹

A person can progress from blacking out to passing out.¹ Passing out or losing consciousness as a result of drinking is a sign of an alcohol overdose, which is a medical emergency.^3,4

Signs and Symptoms of Alcohol Blackout

The signs or symptoms of blackouts can be challenging to identify because people who black out are completely able to partake in complex behaviors. According to the NIAAA, people who black out may engage in conversations, drive automobiles, and perform other behaviors they can recall later–such as spending money, talking, or having unprotected sex. People don’t remember these behaviors because their memories are not transferred into their mind’s long-term storage.^5,6

Alcohol blackout symptoms that may occur are similar to symptoms of intoxication and may include:

• Dizziness.
• Headaches.
• Muscle spasms.
• Vision changes.
• Difficulty speaking.

Though as mentioned earlier, the person may not be aware that they are blacked out.

What Causes Blackouts?

Blackouts are often linked to binge drinking, but they can also occur when people combine certain medications (such as benzodiazepines) and alcohol.¹

According to the Centers for Disease Control and Prevention (CDC), binge drinking occurs when a man has 5 or more drinks or a woman has 4 or more drinks in about 2 hours. It might also include a pattern of drinking that raises your blood alcohol content (BAC) to 0.08g/dl or more.⁷ Blackouts usually occur when your BAC is 0.16% or higher, which often happens when people ingest alcohol too quickly and their bodies aren’t able to effectively process it out of their systems. The overload of alcohol in your bloodstream causes a rapid increase in BAC, which can increase the risk of blackouts.¹

What Happens to Your Body When You Black Out?

The technical term for the type of memory loss that people typically experience during a blackout is known as anterograde amnesia. This means that you cannot form or store new memories. While scientists don’t fully understand the chemical mechanisms behind blackouts, they know a specific area of your brain responsible for the memory (i.e., the hippocampus) no longer functions properly when someone experiences this phenomenon.⁸ Alcohol is believed to change the way that important receptors in your brain act. This leads to the impairment of steroid production, which weakens the connection between brain cells and can impact learning and memory.⁹

Furthermore, using certain medications, especially when combined with alcohol, such as benzodiazepines like diazepam, “z-drugs” used for insomnia such as zolpidem (Ambien), and marijuana, can increase the risk of temporary memory lapses and blackouts, especially in younger people.^6,10

Is Blacking Out a Sign of an Alcohol Use Disorder?

People who blackout while drinking don’t necessarily have an alcohol use disorder (AUD), which is the diagnostic term used to describe addiction. However, the NIAAA indicates that experiencing even one blackout should be a sign of concern that prompts someone to reconsider their relationship with alcohol and to perhaps consult with their healthcare provider.¹

Effects of Excessive Drinking and Blackouts

If you misuse alcohol in ways that are harmful to your health, including binge drinking or high-intensity drinking, you can experience many different short- and long-term effects that can occur in addition to blackouts.^1,7,11

The short-term effects of alcohol misuse can include:^11,12

• Accidents.
• Injuries.
• Violent behavior.
• Unprotected sex.
• Alcohol poisoning.

Alcohol misuse over long periods of time can contribute to the development of many serious consequences, including:¹¹

• Heart disease.
• Stroke.
• Liver damage.
• Liver cancer.
• Breast cancer.
• Bowel cancer.
• Pancreatitis.

Who is Most At Risk for Blacking Out?

Anyone is capable of experiencing an alcohol-related blackout if their blood alcohol concentration reaches roughly 0.16%. However, blackouts can also occur at lower BAC levels if people mix alcohol with sleep and/or anti-anxiety medications.⁷

Generally speaking, however, blackouts are likely to occur when alcohol enters the bloodstream quickly. Drinking on an empty stomach or binge drinking can lead to this rapid rise in BAC.⁷

While women tend to reach a higher peak BAC faster than men—mostly because they usually weigh less than their male counterparts—binge drinkers are also at risk for blackouts. According to data from the 2021 National Survey on Drug Use and Health, among the 133.1 million people who consumed alcohol in the U.S., roughly 45% had participated in binge drinking in the last month.

According to the data, binge drinking was most prevalent among adults aged 18 to 25, which made up 29% of this group. Adults 26 and older along with adolescents aged 12 to 17 accounted for approximately 22% and 4% of binge drinkers, respectively.¹³

How to Avoid Blackout Drinking

To avoid alcohol-related blackouts, drink only in moderation—or abstain from use—and avoid mixing alcohol with other substances. The CDC suggests several tips to cut back on drinking and maintain moderate drinking levels:¹⁴

• Set a limit. Learn about the CDC’s Dietary Guidelines for moderate drinking, and explore its definition of a standard drink. Then make a plan for your drinking that includes the number of days per week you plan to drink and the quantity of drinks you plan to consume within these guidelines.
• Count your drinks. It’s easy to forget how many drinks you’ve had over a given period of time. So consider counting your drinks via a simple paper and pencil method or via a tracking app or phone-based notation.
• Seek support. Enlist the help of family members, healthcare providers, and/or friends to support your moderation or sobriety efforts.
• Control your triggers. People, places, events, and more may prompt you to drink more than usual. So it may help to assess your triggers and make plans to avoid or mitigate them before they occur.

Of course, abstaining from alcohol use may be the best way to avoid blackouts and ensure your health and well-being. If you’re struggling to maintain sobriety, American Addiction Centers can help. With treatment facilities scattered across the country, AAC offers detox, inpatient and outpatient treatment, sober living, and more. Contact AAC at to explore your options and take the first steps toward recovery today.

Frequently Asked Questions: Blackouts

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