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Alcohol Blackout

    What Causes Alcohol Blackouts?

    Blackouts tend to begin at blood alcohol concentrations (BACs) of about 0.16 percent (nearly twice the legal driving limit) and higher. At these BACs, most cognitive abilities (e.g., impulse control, attention, judgment, and decision-making) are significantly impaired. The level of impairment that occurs at such high BACs makes the intoxication level associated with blackouts especially dangerous.

    Blackouts are more likely when BACs rise very quickly—that is, usually when people drink on an empty stomach or when they engage in “shotgunning” (taking a drink from a bottle that’s already open).

    Getting to an Alcohol Blackout doesn’t necessarily mean that a person is unconscious or went to sleep because of too much alcohol consumption. According to the piece ‘Blackout Drinking: Impaired Judgement, Memory Loss, and Other Harmful Effects’, published by The American Addiction Centers, “people often continue to interact with others, engage in routine or potentially dangerous behaviors, and even continue to drink. People who black out may drive themselves home, engage in a sexual encounter, destroy property, spend too much money, or choose other risky behaviors.

    “People who have alcohol blackout are more likely to physically injure themselves. They have also been known to walk home, brush their teeth, eat meals, or go through other normal behaviors. They do not remember these behaviors because their brain does not move those experiences into memory. Once the person begins to sober up, the brain will begin to process memories normally again”. [1]

    Effects of Alcohol Blackout on the brain

    For a long period of time, alcohol was thought of as a general depressor for the central nervous system. But now the consensus is those specific regions of the brain are selectively vulnerable to the acute effects of alcohol. A common Alcohol Blackout behavior is (a clear example of this) when the person is temporarily unable to form new long-term memories while relatively maintaining other skills such as talking or even driving. 

    A person cannot remember something that the brain did not record. Alcohol blackout interferes with receptors in the brain that carry signals between neurons or brain cells. Alcohol blackout affects some brain cells differently than others—it can inhibit some and later activate others—causing them to manufacture steroids that prevent memory formation.

    Alcohol Blackout
    Alcohol interferes with receptors in the brain that carry signals between neurons or brain cells.

    The steroids produced by the alcohol-affected brain cells can reduce the strength of the brain’s connections between brain cells which is critical for learning and memory. The steroids interfere with synaptic plasticity or the brain’s communication system of passing signals between cells. This communication system is a necessary component of memory formation. Keep in mind that drugs can cause blackouts, too. [2]

    As stated by the scientific research,  ‘Alcohol-Induced Blackout’, H. Lee,S. Roh, D. Kim, published by International Journal of Environmental Research and Public Health, “a recent study showed that alcohol can cause retrograde memory impairment, that is, blackouts due to retrieval impairments as well as those due to deficits in encoding. Alcoholic blackouts may be complete (en bloc) or partial (fragmentary) depending on the severity of memory impairment. In fragmentary blackouts, cueing often aids recall”. 

    “Memory impairment during acute intoxication involves dysfunction of episodic memory, a type of memory encoded with spatial and social context. Recent studies have shown that there are multiple memory systems supported by discrete brain regions, and the acute effects of alcohol on learning and memory may result from alteration of the hippocampus and related structures on a cellular level, they added”. [3] 

    Dangers of Alcohol Blackouts

    Alcohol blackout is a stage of alcohol intoxication that can be very dangerous and lead to life-threatening situations. We’re used to normalizing this level of intoxication, but if you are with a person who’s experiencing this, the experts recommend calling emergencies right away.  “At worst, it is possible to pass out while experiencing an alcohol blackout. This is likely due to a large quantity of alcohol in the body, and it could lead to choking on vomit, suffering a head injury from falling, or experiencing alcohol poisoning.

    The individual may also suffer seizures due to the amount of alcohol in their body. A person who is exhibiting unusual, risky behavior or who passes out while drinking needs medical attention to prevent alcohol poisoning problems. Call 911 immediately”. [1]

    Is Alcohol Blackout a Sign of Alcohol Use Disorder?

    Not everyone is equally prone to Alcohol Blackout. Recent studies have shown that some brains are more likely to suffer blackouts produced by heavy alcohol consumption than others. In particular, it affects some neural pathways that move memories from short-term to long-term storage.

    As a result, people who binge drink may struggle with memory loss regarding the previous evening. It can be a sign of potential Alcohol Use Disorder, but not everyone that has this disorder suffers from Alcohol Blackouts, only about 40 percent of the population is prone to blackouts when drinking heavily.

    According to the American Addiction Centers, “heavy alcohol consumption, especially when it occurs routinely, has been associated with brain damage as well as damage to several other organ systems in the body. However, there is little to correlate Alcohol-Related Blackouts and brain damage. While a person who blacks out from drinking too much regularly will likely begin to experience brain damage, this is because they drink too much too often. Alcohol Blackouts are only symptoms that occur when they drink too much”.

    Alcohol Blackout
    Heavy alcohol consumption, especially when it occurs routinely, has been associated with brain damage as well as damage to several other organ systems in the body.

    They also added, “experiencing a blackout after drinking does not mean that a person has a substance abuse problem, but it does mean that they drank more than their body could process over the course of a day or evening. People who often complain about memory loss or blacking out after drinking are more likely to have alcohol use disorder, indicated by the fact that they consume alcohol on a regular basis, not that they experience blackouts.

    “However, people who have alcohol blackout frequently from drinking too much are also likely to have a higher tolerance to alcohol, so their BAC will often be higher than 0.15 when they experience a blackout. For people with a higher tolerance to alcohol, a BAC of 0.2 or greater leads to a blackout. This is extremely dangerous since life-threatening alcohol poisoning begins at a BAC of 0.3”. [1]

    Symptoms and Levels of Intoxication

    What happens when you blackout from alcohol? According to the levels of intoxication a person can have in their body, there are some general symptoms that can be experienced. For reference, one unit is a 12-ounce beer; a 5-ounce glass of wine; or a 1.5-ounce shot of liquor, whether a straight shot or in a mixed drink.

    • 4-6 drinks: The brain begins to experience the effects of alcohol. Judgment and decision-making abilities are impaired. The person’s reaction times will get slower, and they will feel lightheaded or woozy; however, the person is still likely to remember events.
    • 8-9 drinks: Reaction times are slowed, and speech slurs. Vision may change, and issues with double vision or loss of focus may appear. A hangover is likely to set in for most moderate to heavy drinkers.
    • 10-12 drinks: Coordination is severely impaired, and the risk of an accident and personal injury is very high. Drowsiness is likely. Dehydration and headache are more likely as the body processes alcohol, which is becoming very difficult for the liver and kidneys. Nausea, vomiting, diarrhea, and indigestion are all likely at this stage as well.
    • More than 12 drinks: Alcohol poisoning is likely. Breathing, heart rate, and gag reflex can all change.

    People who are not prone to blackouts may experience all of these symptoms in an evening of heavy drinking and remember them the next day. Those who are more prone to blackouts, however, will begin to experience them around 4-6 units of alcohol, especially when consumed in one hour; that puts the person’s BAC at 0.15 or higher.

    The liver can only process one unit of alcohol per hour. When a person consumes two units of alcohol in one hour, their BAC reaches 0.08, and they legally cannot drive. They must wait until their liver has processed their beverages before they can safely get behind the wheel. [1]

    If you or someone you love, think they are experiencing some Alcohol Use Disorder symptoms, or having too many Alcohol Blackouts lately, know that We Level Up California alcohol rehab center can provide the tools to recover from Alcoholism with professional and safe treatment.  Feel free to call us to speak with one of our counselors.  We can inform you about this condition by giving you relevant information.  Our specialists know what you are going through.  Please know that each call is private and confidential.


    [1] ‘Blackout Drinking: Impaired Judgement, Memory Loss, and Other Harmful Effects’, published by The American Addiction Centers

    [2] ‘How Getting Blackout Drunk Blocks New Memories From Forming’ –

    [3] ‘Alcohol-Induced Blackout’, Hamin Lee,Sungwon Roh, Dai Jin Kim, published by International Journal of Environmental Research and Public Health

    [4] Alcoholism Treatment –