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Who Answers?Alcohol-induced blackouts, or memory lapses that occur while intoxicated, are reported by nearly 50% of people who drink alcohol. Blacking out from alcohol is dangerous and could lead to injury or be life-threatening.1
What Is Blacking Out?
Alcohol interferes with memory consolidation due to its effects on the memory center of the brain called the hippocampus.2
Blackouts often occur due to severe binge drinking called high-intensity drinking. High-intensity drinking occurs at 2 times the binge-drinking thresholds of four drinks per day for women and five drinks per day for men.2
There are two different types of blackouts: fragmentary blackouts and “en bloc” blackouts.
Fragmentary Blackouts
Fragmentary blackouts, sometimes referred to as grayouts or brownouts, are the most common type.
When you have a fragmentary blackout, your event memories are spotty, with “islands” of memories separated by missing time periods for which you have no recollection.2
“En Bloc” Blackouts
“En bloc” blackouts are more severe than fragmentary blackouts. These blackouts occur when you have complete amnesia spanning hours.
During “en bloc” blackouts, memories do not form and, therefore, can never be recovered. According to your existing memory, these events never happened.2
How Much Alcohol Do You Have to Drink to Blackout?
Typically, blackouts begin at a blood alcohol concentration (BAC) of 0.16 or higher, which is more than double the legal limit to drive.
In some circumstances, blackouts can also occur at a lower BAC, such as when people take certain sleep or anti-anxiety medications or when alcohol enters the bloodstream quickly and there is a rapid rise in BAC. This may happen when you drink large quantities at once or if you drink on an empty stomach.2
However, it is rare for blackouts to occur at BACs lower than 0.06.1
Is Blacking Out from Alcohol Bad for You?
Blacking out is dangerous for many reasons. It can cause both physiological and psychological damage.
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Help is standing by 24 hours a day, 7 days a week.Who Answers?Psychological Damage
Psychologically, it can create feelings of shame or regret if you say or do things that you wouldn’t normally do or put yourself in unsafe situations and have no recollection of what happened.
Physiological Damage
Physiologically, drinking enough to black out disrupts the normal function of the brain, causing memory loss and impaired cognition. Frequent blackouts can be detrimental to the brain and may alter the structure of the brain’s neural network, causing long-term cognitive impairment.3
Blackouts increase your risk of physical injury or death.1 Drinking enough to blackout can also lead you to act in a way you would not when sober. For many people, due to the reduced inhibitions of intoxication, this behavior can be physically dangerous such as driving or otherwise risky such as unprotected sex.4
Research indicates that blacking out is associated with increased suicidal ideation in both women and men and increased non-fatal suicidal attempts in men.1
Is Blacking Out the Same as Passing Out?
Blacking out is not the same as passing out.
Passing out means you have fallen asleep or lost consciousness as a result of drinking too much. When you black out, you are still awake and able to interact with the world, but your brain stops forming new memories.
However, if you drink enough, you may also pass out following a blackout.2
How Do You Know if Someone Has Blacked Out?
While you may notice many signs of intoxication, there is no objective way to tell if a person has blacked out from drinking.1
However, if you notice any signs of alcohol poisoning, you should seek medical attention immediately. Seek immediate medical attention for:8
- Vomiting
- Seizures
- Mental confusion
- Difficulty remaining conscious
- Slowed heart rate
- Trouble breathing
- Low body temperature
- Clammy skin
- No gag reflex
Is Blacking Out Alcohol Poisoning?
Blacking out is not the same thing as alcohol poisoning. Alcohol poisoning occurs when very high levels of alcohol enter the body, shutting down critical areas of the brain that govern body temperature, heart rate, and breathing, which can result in death.5
Alcohol poisoning and loss of consciousness typically occur at blood alcohol concentrations of 0.25 or higher, with coma and death possible at BACs reaching 0.40.6
Blacking out can happen at much lower BACs.3 Therefore, you can black out without experiencing alcohol poisoning. But, if you drink enough to reach the level of alcohol poisoning, it is highly likely that you have already blacked out.
Are Certain People More Susceptible to Blacking Out?
Some people may be more susceptible to blacking out from drinking than others. Not everyone who drinks heavily will experience a blackout.
Many influencing factors may affect whether or not a person blacks out, including:3
- Quantity of alcohol consumed
- Speed of drinking
- Physiological differences
- Genetics
- Environmental influences
Adolescents and Students
Blackouts are common in healthy adolescents and young adults. More than 50% of college students report experiencing a blackout at some point.1
Adolescents and young adults can also be more susceptible to blackouts because they are often encouraged to binge drink.3 Because their brains are still developing, they may also be more vulnerable to the adverse effects of alcohol.4
Women
Some studies show that women are more likely to black out from alcohol than men, but other studies have shown no significant difference.1 However, women do typically weigh less than men and have less water in their bodies, which could make them more susceptible when drinking a similar amount.2
Alcohol Dependence and Addiction History
Alcohol dependence also increases the risk of blackouts. People with alcohol dependence experience blackouts more frequently.1
Research finds that people with a family history of alcohol misuse are more likely to experience blackouts. It is not yet fully clear whether it is due to environmental or biological factors or a combination of both.1
Prenatal Exposure
Researchers have also found that prenatal alcohol exposure is associated with higher rates of blackouts as an adult, suggesting that people can be born with a vulnerability to blackouts.7
Does Blacking Out Mean You’re an Alcoholic?
Blacking out does not necessarily mean you’re an alcoholic. Alcoholism, clinically designated as mild, moderate, or severe alcohol use disorder, is a set of behaviors and symptoms. While blacking out was first documented as an indicator of alcoholism by Elvin Morton Jellinek in 1946, it is now understood that blacking out can be experienced by anyone who drinks alcohol, even those who drink infrequently.4
In fact, you could go years without drinking any alcohol and drink heavily one night and end up blacking out. It only takes one night of binge drinking to cause a blackout.2
However, blacking out is still a cause for concern. If you are experiencing blackouts at all, you may consider evaluating your relationship with alcohol.
Because feeling unable to control how often or how much you drink is one of the criteria of alcohol use disorder, multiple blackouts when you do not mean to drink as much on each occasion could be a sign that you should be assessed by a mental health professional.
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Help is standing by 24 hours a day, 7 days a week.Who Answers?What Does It Mean if I’m Blacking Out From Alcohol Easily?
If you find that you are blacking out from alcohol easily or more often than normal, it may be time to look at your drinking patterns. Blacking out usually occurs as a result of binge drinking or drinking too much too fast.4 Ask yourself, “Am I drinking too fast or drinking too much alcohol in one setting?”
If you are blacking out easily even at lower levels of alcohol consumption, it may be due to other factors. If you are taking certain medications or mixing alcohol with other drugs, this could cause more frequent blackouts.2 Some people may also be more susceptible to blacking out due to physiological and genetic differences.3
Regardless of the exact reason for your frequent blackouts, blacking out easily is a clear sign of a need to evaluate alcohol use and make changes, potentially with the help of your doctor or an addiction treatment specialist. Each time you black out, you are putting yourself at risk.
Blacking out means that brain damage is occurring particularly to the hippocampus, the brain’s memory center.2 Blackouts also increase your risk for physical injury, psychological problems, and death.1
Any blackout from drinking is a cause for concern. The more often blackouts occur, the more concerned you need to be.
If you are continuing to experience blackouts from alcohol, but are struggling to control your alcohol use, seek evaluation for alcohol use disorder (AUD) and professional treatment.
To learn more about alcohol addiction treatment options, call
800-948-8417
Who Answers?
to speak with an addiction treatment specialist.
Resources
- Weatherill, R. & Fromme, K. (2016). Alcohol-induced blackouts: A review of recent clinical research with practical implications and recommendations for future studies. Alcoholism: Clinical & Experimental Research, 40(5), 922-935.
- National Institute on Alcohol Abuse and Alcoholism. (2021). Interrupted Memories: Alcohol Induced Blackouts.
- Jackson, J., Donaldson, D., & Dering, B. (2021). The morning after the night before: Alcohol-induced blackouts impair next day recall in sober young adults. PLOS ONE, 16 (5), e0250827.
- Hermens, D. & Lagopoulos, J. (2018, January 18). Binge Drinking and the Young Brain: A Mini Review of the Neurobiological Underpinnings of Alcohol-Induced Blackout. Frontiers of Psychology, 9(12).
- University of Notre Dame. (2022). Blood Alcohol Concentration.
- Centers for Disease Control and Prevention. (2015, January 6). Alcohol Poisoning Deaths.
- Miller, M., Merrill, J., Singh, S., DiBello, A., & Carey, K. (2019, December 01). College Students Knowledge of Blackouts and Implications for Alcohol Intervention: A Qualitative Analysis. Psychology of Addictive Behavior, 32(8), 933-943.
- National Institute on Alcohol Abuse and Alcoholism. (2021). Understanding the Dangers of Alcohol Overdose.