18 Minutes

Edited & medically reviewed by THE BALANCE Team
Fact checked

Blacking out drunk is something that at least 50% of drinkers have suffered at some point in their lives according to studies. In this article, we will discuss Blackouts and what blackouts are. The relationship of blackouts with alcohol, what alcohol-related blackouts are and what could be the cause of them; what happens when you blackout drunk, what symptoms are, and what the side effects of it are. We will also discuss whether or not it affects the brain and how it affects the brain.

A blackout is a condition that is known to be temporary and affects your memory. It is looked at as a loss of time. Blackouts mostly occur when your body’s alcohol levels are high. Alcohol impairs your ability to form new memories while intoxicated. It cannot remove memories that were formed before being intoxicated.

Fetal Alcohol Syndrome Symptoms and Causes

As you continue to drink more alcohol and your blood alcohol level rises, the length and rate of memory loss will slowly incline. The memory loss amount may vary from one person to another. A study showed that the odds of having a blackout is around 50% when your blood alcohol level reaches 0.22 percent. You might be unable to remember the time that’s passed when your blood alcohol level is above that mark.

There are several factors that may affect your blood alcohol level. These include:

  • Gender;
  • Weight;
  • The alcohol consumed type;
  • The speed at which the alcohol is consumed.

It should be noted that there is not a specific number of glasses that can initiate a blackout. The amount of alcohol you have taken in each drink and the effect that the certain type of alcohol has on you is what it all comes down to.

An alcohol blackout normally is a reference to the memory loss that can occur after drinking a lot of alcohol at the same time. Sometimes this is also called an “alcohol-induced blackout” or an “alcohol-induced amnesia.” Blackouts may refer to both partial or complete memory loss with the first sometimes also known as “gray out.” Too many blackouts are a usual sign of alcohol disorder and abuse. As your blood alcohol level increases, your brain may not be able to form new memories, although you’re still wide awake and interacting with your surroundings. The higher an individual’s blood alcohol concentration (BAC), the more memory loss he or she is potentially going to face.

Alcohol and Depression

Alcohol blackouts do not normally affect the memories you made before the blackout happened. Instead, you will actually remember everything rather vividly up to a certain extent, at which point your memories become fuzzy and eventually go away completely. As the alcohol effect starts to wear off or an individual’s blood alcohol concentration level begins to lower, he/she will start to create memories once again.

Keep in mind that blacking out and passing out from drinking is not the same thing. During an alcohol blackout, you’re still able to talk, make decisions, and continue drinking. When you’re passed out from alcohol, you will be unconscious and won’t respond to stimuli including people nudging you or speaking to you.

Since everyone is different, people who are in the condition of a blackout due to drinking might look like they are functioning normally for the most part or could seem so intoxicated that they have issues with walking or even standing. As people are not in complete control of their bodies in such a state, they are very much likely to engage in risky behaviors such as driving while drunk or unsafe sex as well.

The reason for someone to blackout from alcohol specifically lies in the inability of the brain to function routinely and efficiently when an individual is under the influence. When you are not drunk, you create memories by receiving sensory input, processing it, and then it is stored in your short-term memory. After that, the incident is shifted over to your long-term memory in the hippocampus by a process known as encoding so that individuals can remember these memories later.

When a person drinks a lot of alcohol, the efficiency of the brain is reduced, and all of these processes of the memory become impaired. Most importantly, heavy drinking is believed to interfere the most with the encoding stage.

As a result, when the blood alcohol level of an individual reaches a specific amount, he or she will start to lose the ability to create and retrieve fresh memories. For a lot of people, an alcohol blackout begins at a blood alcohol concentration level of about 0.14, but the onset of an alcohol blackout may vary from one person to another.

Alcohol can affect decision-making, destroy your impulse control, and it can also lower your inhibition. Alcohol intoxication may very well impair the ability to recall events, react, walk, and talk. The reward pathway in the brain regulates these activities. This part of the brain may also build up a tolerance to alcohol for the long term. However, when a blackout happens the hippocampus (which is at a depth in the brain and responsible for forming memories as mentioned earlier) cannot create long-term alcohol toleration.

How Long Does Alcohol Stay in Your System?

Since most parts of the brain are tolerant of alcohol, at the stage of a blackout a person that is drunk or intoxicated may very well function normally. Even though the individual may still drive, walk, eat, have sex, and make conversation, they will be unable to memorize any of it. This could be tough for other people to understand that an individual is in a blackout due to this state that makes it look like the person is aware.

Certain behavioural symptoms may indicate an alcohol use disorder when drinking becomes out of control and a person grows closer to addiction. During this period, a person may hide alcohol and lie about their drinking habits, or become defensive when questioned about their drinking.

A person may continue to drink despite harm to their health, job, and relationships. In many situations, a person’s interest in activities or hobbies that they previously liked will wane. Many people may struggle to keep their drinking under control, resisting frequent and compulsive desires to consume more alcohol (cravings).

When an user starts to drink on a daily basis, they may build a tolerance to alcohol and require more to achieve the desired effect. Other physical and mental symptoms of alcohol misuse and addiction may appear in addition to these changes:

  • acting in ways that are out of character
  • anxiety
  • appetite shifts
  • Depression 
  • Double vision. 
  • sleep disruption
  • dizziness which in turn affects reaction time and mood swings
  • vomiting and nausea
  • Anxiety attacks
  • a lack of concentration a lack of reactions
  • restlessness
  • drowsiness at inconvenient moments
  • speech that is slurred
  • violent behaviour, trembling or trouble walking straight

The reason why this understanding these symptoms is important is that it might be difficult to tell if someone is having a blackout because many individuals continue to talk and act normally. It’s also conceivable that someone is very inebriated but isn’t blacking out. To put in simple words, with the aim to discuss the most common symptoms to look out for (from the list above) the most common indications and symptoms of an alcohol blackout are difficulty walking or following a discussion difficulty talking or following a conversation repeating themselves during a chat impaired judgement and hazardous conduct involvement, distractibility and visual impairment due to forgetfulness. The more alcohol a person consumes and the higher his or her blood alcohol content, the more likely he or she is to have blackout symptoms.

Addiction may destroy a person’s life, health, and relationships if they don’t get assistance. Recovery from an alcohol addiction is, fortunately, achievable with the correct combination of therapy.

A blackout happens after a period of excessive drinking or when a big amount of alcohol is consumed. Binge drinking is a significant contributor to this condition. Binge drinking happens when a person consumes enough alcohol to raise their blood alcohol content to 0.08 g/dL, according to the National Institute on Alcohol Abuse and Alcoholism. This usually takes around two hours and involves the following steps:

  • For women, four or more drinks are required.
  • For men, five or more drinks are required.

While the amount of alcohol ingested has a significant influence on this disease, experts believe that the manner in which it is consumed, as well as the rate at which it is drunk, is also important. While a high blood alcohol concentration (BAC) is a risk factor for memory blackout, scientists believe that a blackout is more likely to occur when a person’s BAC climbs to a high level in a short amount of time. According to certain research, those who attained a high BAC slowly did not have a blackout, but those whose BAC jumped fast did. People who drink alcohol quickly on an empty stomach may be at a higher risk of developing this disease, as these activities can quickly elevate blood alcohol levels. Furthermore, scientific data identifies many variables that may increase a person’s risk of blackouts:

  • When you drink due to fatigue.
  • Intoxication occurs frequently.
  • Aspects of genetics
  • going on a bender
  • chugging or gulping beverages
  • a diagnosis of alcoholism for the rest of one’s life
  • a previous head injury or insult

It is also important to ascertain both, the long term, and the short term effects on an Alcohol Blackout. The following are some of the short-term consequences of alcohol abuse: 

  • Accidents.
  • Anxiety brought on by alcohol.
  • Depression brought on by alcohol.
  • Accidents.
  • Injuries.
  • Violent conduct.
  • Sex that isn’t protected.
  • Alcohol poisoning is a serious condition.

Long-term alcohol abuse can lead to the development of a number of severe effects, including:

  • Heart disease is a serious condition.
  • Stroke.
  • Damage to the liver.
  • Cancer of the liver.
  • Breast cancer is a disease that affects women.
  • Cancer of the bowel.
  • Pancreatitis.

Not everyone who consumes a large amount of alcohol in a short period of time will have a blackout. However, the effects of alcohol on the brain are primarily to blame for those who do. Alcohol can impair a person’s memory and ability to think coherently even in little doses. The larger the amount of alcohol ingested, the more these critical cognitive functions are harmed.

According to studies, a person may recall an incident minutes after it occurred, but owing to a blackout, they may not recall it a half hour later or the next day when sober. This implies that alcohol interferes with the conversion of short-term memories to long-term memories.

Making and recalling memories is a multi-step process. Before a memory can be recovered, it must first be created and stored. Alcohol has been shown in studies to have a detrimental impact on each stage of this process. Furthermore, alcohol damages the hippocampus, a brain area that is important for the formation of new autobiographical memories, or recollections about one’s own experiences.

According to studies, a person may recall an incident minutes after it occurred, but owing to a blackout, they may not recall it a half hour later or the next day when sober. This implies that alcohol interferes with the conversion of short-term memories to long-term memories.

Making and recalling memories is a multi-step process. Before a memory can be recovered, it must first be created and stored. Alcohol has been shown in studies to have a detrimental impact on each stage of this process. Furthermore, alcohol damages the hippocampus, a brain area that is important for the formation of new autobiographical memories, or recollections about one’s own experiences.

Alcohol and blackouts resulting from an overdose of alcohol clearly affects the brain, as seen by difficulty walking, blurred vision, slurred speech, delayed response times, and poor memory. Some of these limitations can be detected after just one or two drinks and disappear fast if drinking is stopped. A person who drinks heavily over a long length of time, on the other hand, may have brain impairments that last long after achieving sobriety. The exact effects of alcohol on the brain, as well as the possibility of reversing the effects of excessive drinking on the brain, are still hot issues in alcohol research today.

Alcohol and Panic Attacks

We do know that frequent drinking may have a wide range of consequences on the brain, ranging from minor memory lapses to chronic and severe disorders requiring lifelong care. And, as considerable research on the influence of alcohol on driving has demonstrated, even moderate drinking causes short–term impairment.

The way and amount to which alcohol affects the brain is influenced by a variety of variables (1), including:

  1. How much and how often a person consumes alcohol;
  2. How old he or she was when they first started drinking and how long they’ve been drinking;
  3. age, education level, gender, genetic origin, and a family history of drinking;
  4. if he or she is at risk as a consequence of prenatal alcohol exposure; and whether he or she is at risk as a result of prenatal alcohol exposure.
  5. his or her overall health condition

This Alcohol Alert examines some of the most prevalent diseases linked to alcohol-related brain damage, as well as the persons who are most vulnerable to impairment. It examines both established and new therapies for the treatment and prevention of alcohol–related illnesses, as well as high–tech techniques that are assisting scientists in better understanding the effects of alcohol on the brain. 

“Have you ever awoken after a night of drinking not being able to recall things that you did or places that you went?” White and his associates questioned 772 college undergraduates about their experiences with blackouts. Of the students who had ever used alcohol, 51% said they had blacked out at some time in their life, and 40% said they had blacked out in the year leading up to the poll. 9.4 percent of respondents who indicated they drank in the two weeks leading up to the poll claimed they blacked out during that period. The students then discovered that they had taken part in a variety of potentially risky activities that they couldn’t recall, such as vandalism, unprotected sex, and driving.

Despite the fact that males drank much more frequently and heavily than women, equal percentages of men and women reported blackouts. This finding shows that, independent of alcohol intake, females—a population that has received little attention in the literature on blackouts—are more likely than men to experience blackouts. Differences in how men and women metabolise alcohol are most likely to blame for a woman’s predisposition to black out more readily. Even when men and women consume the same quantity of alcohol, females may be more sensitive to milder types of alcohol-induced memory problems. This begs the question, are women more vulnerable to the effects?

Many of the medical effects of alcohol abuse and thus the blackouts that result, are more severe in women than in males. After fewer years of severe drinking, alcoholic women acquire cirrhosis , alcohol–induced heart muscle damage (cardiomyopathy), and nerve damage (peripheral neuropathy than alcoholic males. However, studies comparing men and women’s susceptibility to alcohol-induced brain injury have come up short.

Two investigations examined brain shrinkage, a typical indication of brain injury, in alcoholic men and women using imaging using computed tomography, and found that both male and female drinkers had substantially higher brain shrinkage than control individuals. Heavy drinking has also been linked to learning and memory difficulties in both men and women, according to studies. The difference is that alcoholic women in these studies reported having been drinking excessively for roughly half as long as alcoholic males. This suggests that, like their other organs, women’s brains are more sensitive to alcohol-induced harm than men’s.

Other research, on the other hand, have not produced such conclusive results. In fact, two studies published in the same issue of the American Journal of Psychiatry opposed each other on the issue of gender-related sensitivity to brain shrinkage in alcoholics. Clearly, more study is needed on this issue, especially because alcoholic women have gotten less scientific attention than alcoholic males, despite the fact that there is evidence that women are more sensitive to the effects of alcohol on several critical organ systems.

People who consume high amounts of alcohol over a lengthy period of time, and as a result suffer blackouts, are at danger of having substantial and long-lasting brain abnormalities. Damage can occur directly as a result of alcohol’s effects on the brain, or indirectly as a result of poor general health or severe liver disease.

Thiamine insufficiency, for example, is frequent in persons with alcoholism and is caused by poor overall diet. Thiamine, commonly known as vitamin B1, is a substance that all tissues, including the brain, require. Meat and poultry, whole grain cereals, nuts, and dry beans, peas, and soybeans are all high in thiamine. 

Many foods in the United States, including breads and cereals, are fortified with thiamine. As a consequence, the majority of individuals get enough thiamine in their diets. Most Americans consume 2 mg per day; the Recommended Daily Allowance for males is 1.2 mg per day and 1.1 mg per day for women. However, up to 80% of alcoholics who suffer blackouts have thiamine deficiency (15), and some of these persons will develop significant brain diseases including Wernicke–Korsakoff syndrome (WKS) (16). WKS is a sickness that comprises of two distinct syndromes: Wernicke’s encephalopathy, which is a short–term and severe illness, and Korsakoff’s psychosis, which is a long–term and disabling condition.

It is a popular misconception that personality changes when one has alcohol, or worse, has a blackout. Personality changes however, according to observers, are not too drastic when a sober person becomes intoxicated. There might be small deviances from normal sober personality, but it is mostly temporary behavioral changes that occur. Due to alcohol induced blackouts, these behavior and personality changes happen because of the effect of alcohol on the brain.

Individuals think their personalities change but scientific research on this still has gray areas. To try and unfold at least some truth, a research was held by a psychological scientist from the University of Missouri, Rachel Winogard. The fact that there is a huge difference in perception of what drunk individuals believe their personality it be like and how observers see it, was taken into account and an experiment was performed on individuals in their drunk and sober states. (Of course, this is due to the fact that the individuals themselves can narrate how they feel internally, while the observers can only tell what is apparent). The researchers conducted their experiment (whose details are omitted in this article due to irrelevance to our question) and concluded that the people rated themselves as having lower levels of extraversion, openness to experience, agreeableness and conscientiousness. On the other hand, the observers reported much fewer differences, and only pointed out extraversion as the personality factor that truly changes.

Moving on, modern research has also highlighted that blackouts are common in people who drink socially. One does not have to have an alcohol use disorder (AUD) in order to get a blackout. It is also known that blackouts can cause a person to behave erratically, engaging in behaviors they may not engage in when sober, such as sexual intercourse with someone who is not a romantic partner. For a person with AUD, moreover, feelings of shame, fear, irritability and discontent follow a blackout. These are also the symptoms of Borderline Personality Disorder (BPD). When a person with BPD has a blackout due to drinking, they will have these symptoms but exaggerated and also accompanied by feelings of wanting to harm themselves. In this way, the two are overlapping each other.

Furthermore, observers, such as wives, children and friends, have noted that abuse occurs or increases when the people they are close to drink. This may cause them to become more aggressive as well. Some may become stressed and moody. Our examples and research conclusions allude to the basic deduction that the effects of alcohol on personality differ from individual to individual, but it is not an enormous change as the general belief supposes.

Blackouts mostly take place at a Blood Alcohol Concentration (BAC) of 0.16 % (or higher). Causes for frequent blackouts vary greatly, from fainting to having epileptic seizures to having a low blood pressure. If an individual is having frequent blackouts, they should check their blood sugar levels throughout the day and see if they are stable or not. If not, then the person should make sure to eat regular healthy meals to keep it in check. One should also keep their blood pressure monitored to know whether sufficient oxygen is reaching the brain, especially if they are chronic drinkers.

They should refrain from ingesting alcohol too quickly ad this can rapidly increase the BAC and cause a blackout even after one drink. Too many blackouts can cause brain damage, particularly the hippocampus and can cause some brain cells to die, leading to permanent memory damage. It is, hence, a cause for concern if blackouts start occurring too frequently – for example every time a person has more than a drink. This should be alarming enough to get professional help, and perhaps finding a therapist who can help the individual leave alcohol.

Loss of consciousness is a blackout, in plain terms. Another aspect of a blackout is memory loss, complete or partial. Huge amounts of alcohol is a major cause of this.

There are two kinds of blackouts that occur after drinking:

  1. En bloc blackout – which is also called complete blackout, where an individual who drank alcohol excessively cannot remember any of the events that happened during the drinking period
  2. Fragmentary memory loss – this is when the person can remember a handful of events that occurred during the drinking period

That said, blackouts can occur without drinking alcohol as well. For example; blackouts that occur in epilepsy. An epileptic episode occur when there is a disruption in the normal neuronal activity in the brain. A seizure may follow, eventually losing consciousness. Blackouts do not happen every time a seizure occurs, but they are a likelihood along with a dozen other symptoms.

Another type of blackout without alcohol drinking is called syncope blackout. This happens when not enough blood reaches the brain and temporary loss of consciousness occurs. In common terms, it is called fainting. One potential cause for this is low blood pressure, which in turn causes less oxygen to get to the brain. A syncope blackout can either be neutrally mediated or it can be cardiac. The former is benign and does not require a medical treatment. It can occur due to low blood pressure or dehydration. The latter, cardiac syncope, is far more serious and it means that the heart is somehow having a problem. Hypertension and tachycardia are examples of causes for cardiac syncope. Without treatment, severe complications or even death can result.

Furthermore, even excess stress can cause a blackout. This type is called a psychogenic blackout, and it is believed that it happens when people feel threatened or think of a threatening memory. A person who gets a psychogenic blackout can faint, lose control of bladder and bowel, go “blank”, not remember anything related to the blackout or start jerking his / her limbs.

We know that alcohol blackouts causes memory loss which can be complete or partial. There are known treatments that can help with memory loss after drinking. Firstly, thiamine supplementation or intravenous thiamine can help. Memantine, a medication for Alzheimer’s, can also improve alcohol related memory loss. It is not certain whether these methods will bring back everything that happened during the drinking period, but it does help significantly. Some moments are never recovered completely.

To fully recover from memory loss from blackouts can only take place is alcohol is left once and for all. This is a huge commitment and a tremendous lifestyle change, which one has to be ready and determined to undertake. Leaving alcohol will most definitely have a positive impact on one’s memory, and make them clear headed in the long run (if they have not already damaged their liver and brain irreversibly). 

Blacking out and passing out is not the same- the two are confused with one another. Blackouts do not let a person create new memories (memory loss aspect), while passing out means falling asleep or losing consciousness. Blackouts can turn into passing out as well. Whatever the case, it is important to learn the dangers of blackouts and try and avoid them from happening. Points to remember while drinking are mentioned in this section.

It is a fact that more than 50 percent of adults have blacked out at least once in their life, proving that people do not really follow warning signs in advertisements and commercials. The following are some ways one can adopt to reduce the chances of blacking out:

  1. Drink slowly
  2. Eat something before drinking
  3. Drink more water and stay hydrated when drinking
  4. Avoid drinking games, chugging and shots of alcohol as it is easy to lose count and overdo
  5. Ask a friend to stay by you to manage your drinking if it starts to get out of hand



The Balance RehabClinic is a leading provider of luxury addiction and mental health treatment for affluent individuals and their families, offering a blend of innovative science and holistic methods with unparalleled individualised care.


a successful and proven concept focusing on underlying causes


0 Before

Send Admission Request

0 Before

Define Treatment Goals

1 week

Assessments & Detox

1-4 week

Psychological & Holistic Therapy

4 week

Family Therapy

5-8 week


12+ week

Refresher Visit

Alcohol Insights

latest news & research on Alcohol
Alcohol Withdrawal Treatment
Alcohol Withdrawal Treatment

Based on the intensity of the withdrawal, individuals with AWS can be managed in an outpatient or inpatient setting

read more
Alcoholism Treatment
Alcoholism Treatment

It is not easy to give up that easily but it’s not impossible either!  The treatment of alcoholism begins with detoxification and ends till you recover fully

read more
Woman sitting at the table with green plants in the foreground.
Alcohol Detox

read more
Cross Faded
Cross Faded

Crossfaded refers to the state of being simultaneously intoxicated by both alcohol and marijuana.

read more


British Psychology Society
Institute de terapia neural
pro mesotherapie
Somatic Experience


Woman & Home
National World
American Banker
Marie Claire
La Nacion
Metro UK
General Anzeiger
Live Science
Mallorca Magazin
Apartment Therapy
Express UK
Manager Magazin
Entrepreneur ME
Khaleej Times
Business Leader
The Guardian
Daily Mail
Mallorca Zeitung
Mirror Uk
The Times
The Standard
The Stylist