Drunk Driving PA

What Does it Mean to be Blackout Drunk?

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Part of the complete guide to understanding addiction

It is no secret that alcohol, when consumed irresponsibly, can cause serious side effects. These can range from mild inconvenience or minor ailments, to life-altering health issues, and even death. One serious side effect of alcohol consumption is blackouts. A 2021 study found that roughly 50 percent of individuals that drink alcohol will experience an alcohol blackout at some point throughout their lives. This risk stands independent of age, gender, or alcohol history. Alcohol intoxication severe enough to cause a blackout is referred to as blackout drunk.

What exactly is blackout drinking? In 2009, The National Institute on Alcohol Abuse and Alcoholism (NIAAA) published a factsheet about alcohol blackouts and defined blackout drinking as alcohol-induced blackouts; gaps in memory based on events that occur during intoxication.

This side effect of alcohol intoxication is commonly confused with passing out (called being passed out drunk), or “blacking out”. Passing out is known as syncope [1] and involves a temporary loss of consciousness; the individual no longer displays voluntary actions such as talking, walking, or general movement. The “blackout drunk” definition is quite different; the individual maintains consciousness but loses all memory of that time period. The individual is often able to continue moving, talking, and interacting - exhibiting apparent control over their actions. However, there is a portion of their brain that has shut down due to alcohol consumption.

Brownout vs. Blackout Drunk

There are two specific types of alcohol-induced blackouts, both related to memory: fragmented blackouts and total blackouts.

Fragmented Blackouts (Brown-outs)

Fragmented blackouts are characterized by an individual experiencing gaps in their memory while also being able to recollect some events. Also known as “gray-outs” or “brown-outs”, fragmented blackouts can be hazardous because they often leave the individual with the false impression that a blackout never actually occurred.

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Total Blackouts

These occur when an individual has absolutely no recollection of what took place during their intoxication. Memories never formed, and therefore cannot be accessed. This condition is also known as an en bloc blackout, and can last for several hours.

Blackout Drinking Risk Factors

An important and often overlooked cause of blackouts are drinking games. There is even a game called blackout drinking game. Drinking games are designed to encourage alcohol consumption, and this can lead to overindulging, lack of tracking consumption, and ultimately intoxication. Because alcohol is being consumed in large quantities over a short period of time, blackouts are very common.

Binge drinking is another cause of alcohol-induced blackouts. Binge drinking is defined as excessive alcohol use – usually more than five drinks – over a short time period. The amount of alcohol ingested, and the length of time in which it was ingested, can often result in blackouts.

A lesser known cause of blackout drinking is combining certain medications with alcohol. This occurs most commonly when alcohol is mixed with benzodiazepines, like Ambien. Such blackout drinking occurs especially in younger individuals.

Studies show that blackouts usually begin at BAC (blood alcohol concentration) of 0.16%. This amount is almost twice the legal driving limit.
Alcohol blackouts can occur at much lower BACs when alcohol is ingested together with certain medications.
Blackouts are far more likely to happen when large amounts of alcohol are drunk quickly, causing a rapid peak in BAC. The amount needed to cause high peaking BAC is lower for females than males, due to their lower average body mass. This is why females are at a higher risk of having blackouts.

What Causes Alcohol Blackouts?

It is clear that both the amount and time period of alcohol consumption play a major role in blackout drinking. However, studying physiological causes will explain why one can become blackout drunk. The medical/scientific term for blackout drinking is anterograde amnesia. This is a condition in which the brain is unable to form or store new memories.

The chemical and neurological changes in the brain which lead to blackout drinking are not yet entirely understood. We do know however, that the part of the brain which shuts down during blackout drinking is the hippocampus [2]. This portion of the brain is responsible for memory, and it stops functioning properly during a blackout.

It is believed that the hippocampus stops functioning because alcohol changes the way in which the brain’s receptors respond. When receptors are not functioning at their normal capacity, steroid production is halted or impaired significantly. This causes the connections between brain cells (through neurons and receptors) to be weakened. When these connections are impaired in any way, learning and memory are negatively impacted.

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Alcohol Blackout Signs and Symptoms

Because it is normal for outsiders not to realize when an intoxicated person is experiencing a blackout, there is a risk of increased danger to themselves and others. This makes it all the more important to be able to recognize the signs and symptoms of this condition in yourself and others. The most common symptoms are physiological, and include:

  • headaches
  • dizziness
  • vision changes
  • muscle spasms
  • difficulty controlling speech.

Of course, these symptoms may or may not be present, and the best way to prevent blackouts is to drink within safe limits.

Alcohol use disorder (AUD) is the medical diagnostic term referring to an individual who suffers from compulsive consumption of alcohol. While alcoholism can definitely lead to alcohol-induced blackouts, not all individuals who experience blackouts have an alcohol use disorder (AUD). A blackout is not necessarily a sign of an AUD but should still raise a red flag, and prompt the individual to begin changing their relationship with alcohol.  

Side Effects and Dangers of Blackout Drinking

Blackout drinking affects an individual’s health and safety as well as the safety of others. Several potential risks include:

  • Making bad choices and not remembering them
  • Being taken advantage of and having no recollection
  • Increased risk of alcohol poisoning
  • Progression from alcohol blackout to loss of consciousness due to alcohol overdose, a serious medical emergency

Because the drinker’s memories are not transferred to long-term storage, they are at great risk for personal, financial, physical, and legal danger. They are able to complete complex tasks like driving, spending money, conversing, and making choices that could lead to physical harm. This places themselves and others at risk.

Prevention and Response to Alcoholic Blackouts

What should one do when blackouts occur while drinking alcohol – either to oneself or another? The greatest concern is safety and prevention. Therefore, if you feel or witness any of the physiological symptoms of blackout, it is important to stop drinking and immediately notify someone. This is a time when the intoxicated individual should not be allowed to make any decisions, operate a vehicle, or spend money. Emergency medical intervention may be needed to prevent alcohol poisoning and other negative side effects.

The best approach to keeping yourself and others safe is by preventing blackouts from occurring in the first place. This requires consuming alcohol responsibly by staying within safe limits, maintaining accountability, and carefully monitoring the speed at which you or others are drinking.

Other ways to prevent blackouts include:

  • Avoiding drinking on an empty stomach. Have a meal or light snacks before and during alcohol consumption.
  • Drinking slowly
  • Staying hydrated


Don’t assume such a situation will never happen to you, or that you’re safe because one blackout didn’t have any negative consequences. While blackout drunk, it only takes one poor choice or bad reaction to significantly impact your life.

Treatment for alcohol addiction is widely available and proven to work successfully. Avenues Recovery, leaders in addiction rehabilitation, offers comprehensive alcohol treatment options to help you find your way back home. Contact us today for addiction advice and to hear how we help you on your journey to a sober, happier future.

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[1] clevelandclinic.org

[2] www.ncbi.nlm.nih.gov

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