How Does Alcohol Affect the Brain?

Short-term effects of alcohol use on the brain are evident – impaired people exhibit difficulty walking, slower reaction times, blurred vision, slurred speech, and memory problems. Some of these effects are identifiable after only a drink or two and rapidly abates once the drinking stops. But alcohol’s effect on the brain goes far beyond short-term manifestations.

Moreover, an individual who consumes an excessive amount of alcohol over an extended period of time may develop brain deficits that continue long after he or she becomes sober.


Researchers now know that heavy drinking can have extensive and longstanding effects on the brain, ranging from memory lapses to a permanent, debilitation condition that requires custodial or palliative care. In fact, even moderate drinking can result in temporary impairment.

Several factors influence how and to what degree alcohol impacts the brain, including the following:

  • How frequently and how much an individual drinks
  • The age that a person begins drinking, and the duration of regular drinking
  • The individual’s age, education level, gender, genetic profile, and family history of alcohol and drug use
  • If the person is at risk due to exposure to alcohol in utero
  • General health status and overall wellness

The following describes some common disorders associated with alcohol-related brain damage and the individuals at a heightened risk for impairment.


Blackouts and Memory Loss

Alcohol use can lead to identifiable memory impairments after just a few drinks, and the extent of the impairment increases in correspondence with alcohol consumption. Large amounts of alcohol, particularly when drank rapidly and/or without food can result in a “blackout” – a period of time in which an intoxicated individual later cannot remember some of all events that transpired.

Blackouts are more common among social drinkers than once thought and can be a result of acute intoxication regardless of whether the consumer is dependent upon (or addicted to) alcohol.

In one study, nearly 800 college undergraduates were surveyed about their experiences with blackouts after a night of drinking. Of those who had ever drunk alcohol, more than half (51%) reported blacking out at some time in their lives, and 40% reported experiencing a blackout in the past year.

Among those who reported consuming alcohol in the two weeks before the survey, 9.4% stated they had a blackout during that time. The students said they learned later than they had engaged in potentially hazardous activities they could not remember including unprotected sex and drinking and driving.


Binge Drinking

Drinkers who experience blackouts generally consume too much alcohol too quickly, causing their blood alcohol concentration to increase rapidly. College students may be at an especially high risk for blackouts, considering a large number engage in binge drinking (defined as consuming four to five or more drinks in two hours for women and men, respectively.)

An equal number of women and men report experiencing blackouts, despite the fact that men tend to drink more often and more heavily. This fact implies that regardless of the amount consumed, women may be at a greater risk than men for experiencing blackouts.

A female’s propensity to black out more easily likely results from variations in how women and men metabolize alcohol. Women may also be more vulnerable than men to lesser forms of alcohol-related memory lapses or impairments, even when both sexes drink similar amounts of alcohol.


Are Women More Vulnerable?

Women are more susceptible to many of the physical and mental consequences of alcohol abuse. For example, women with alcoholism develop liver cirrhosis, alcohol-related heart disease, and nerve damage after fewer years of heavy alcohol consumption than do male drinkers. But what about brain damage?

In two studies, brain shrinkage (a common indicator of brain damage) was compared between alcoholic men and women and control subjects, and both revealed that drinkers had significantly greater shrinkage. Research has also shown that both women and men have comparable learning and memory impairments as a consequence of heavy alcohol consumption.

The main difference was that alcoholic females reported that they have been using alcohol excessively for only around half the time of the alcoholic males – suggesting that women’s brains, similar to other organs, may be more susceptible to alcohol-related damage than men’s.


Brain Damage via Other Causes

Individuals who have been consuming excessive amounts of alcohol for long intervals face the risk of developing severe and persistent brain changes – damage may be a consequence of alcohol’s direct effects or may result indirectly from poor health or liver disease.

Moreover, a deficiency in thiamine is a common result for individuals with alcoholism and results from poor nutrition. Thiamine (B1) is a key nutrient needed by all tissues, and the brain is no exception. Thiamine can be found in foods such as meat, whole grains, nuts, beans, and peas. In fact, many foods in the U.S. are often fortified with thiamine, such as bread and cereals. As a result, most people ingest a sufficient amount of thiamine.


Wernicke–Korsakoff Syndrome (WKS)

As many as 4 in 5 alcoholics, however, experience a thiamine deficiency, and some of these will eventually develop brain disorders such as Wernicke-Korsakoff syndrome (WKS.) WKS is a condition that includes two separate syndromes, a brief but severe disease known as Wernicke’s encephalopathy and a longstanding and debilitation conditions referred to as Korsakoff’s psychosis.

Wernicke’s encephalopathy symptoms include confusion, oculomotor disturbances (nerve paralysis of the eyes) and poor muscle coordination. For example, people with Wernicke’s may be too confused to navigate out of a room or may not even be able to walk.

A large percentage – around 80-90% – of alcoholics with Wernicke’s also develop Korsakoff’s psychosis, a long-term syndrome characterized by learning and memory impairments. People with Korsakoff’s are forgetful, easily frustrated, and have difficulty with coordination.

While these patients have trouble recalling old information, it is their difficulty in obtaining new information that is the most prominent. For example, these people may be able to discuss, in detail, an event earlier in their lives, but an hour later may not remember engaging in the conversation.


Liver Disease

A relatively unknown consequence of liver dysfunction (e.g., cirrhosis) is damage to the brain. This damage can result in a severe and potentially fatal brain disorder referred to as hepatic encephalopathy, a condition that can cause altered sleep patterns, mood, and personality, in addition to anxiety and depression, shortened attention plan, and problems with coordination.

Researchers have studied the brain regions of patients with alcoholic liver disease and found that at least two toxic byproducts, manganese and ammonia, play a role in the development of hepatic encephalopathy. Liver cells damaged by alcohol use permit an excessive amount of these harmful substances to enter the brain and damage brain cells.


Treatment for Alcoholism

The best way to prevent alcohol-related brain damage, whether short- or long-term, is to stop drinking and participate in our evidence-based treatment program. Our center offers comprehensive, evidence-based therapies and counseling in both inpatient and outpatient formats.

Our professional staff specialize in addiction and can provide our patients with the tools they need to succeed at recovery and sustain long standing wellness and sobriety. Recovery from addiction is a lifelong process, but you don’t have to do it alone. With our help, you regain your sanity and enjoy the happy and fulfilling life you deserve.


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