Alcohol begins affecting a person's brain as soon as it enters the bloodstream. In a healthy person, the liver quickly filters alcohol, helping the body get rid of the drug. However, when a person drinks to excess, the liver cannot filter the alcohol fast enough, and this triggers immediate changes in the brain.

Over time, excessive alcohol consumption can damage both the brain and liver, causing lasting damage.

Excessive alcohol consumption can have long-lasting effects on neurotransmitters in the brain, decreasing their effectiveness or even mimicking them. Alcohol also destroys brain cells and contracts brain tissue. Some people with a history of excessive alcohol use that further damage brain function.

The precise symptoms of alcohol-related brain damage depend on a person's overall health, how much they drink, and how well their liver functions, among other factors.

A woman with a headache from alcohol
Moderate consumption of alcohol may cause a depressed mood, loss of inhibition, and sleepiness.

As soon as alcohol enters the bloodstream, it changes how the brain functions. Moderate consumption of alcohol may cause the :

People with severe symptoms of intoxication or symptoms that last many hours are at risk of alcohol poisoning.

The ethanol in alcohol acts like a poison. When the liver is not able to filter this poison quickly enough, a person can develop signs of alcohol poisoning or alcohol overdose. An affects the brain's ability to sustain basic life functions.

Symptoms include:

  • vomiting
  • seizures
  • slow heart rate
  • difficulty staying awake
  • fainting
  • low body temperature
  • low gag reflex, which can increase the risk of choking if a person vomits
  • clammy skin

An untreated alcohol overdose can be fatal. Severe alcohol overdoses may cause permanent brain damage even if the person survives.

The higher a person's blood alcohol concentration, the higher their risk of alcohol overdose. The heavy consumption of high-alcohol drinks is more likely to cause alcohol poisoning. People who have smaller bodies, drink alcohol less frequently, or have a history of liver disease are also more vulnerable to alcohol poisoning.

Over time, alcohol abuse can cause permanent brain damage.

Wernicke-Korsakoff syndrome

One form of alcohol-related brain damage is Korsakoff syndrome. Korsakoff syndrome often appears after an episode of Wernicke's encephalopathy, which is acute alcohol-related brain dysfunction.

The two conditions, together called Wernicke-Korsakoff syndrome, happen in people who are severely (vitamin B-1). Alcohol abuse makes it more difficult for the body to absorb this nutrient, but other issues, such as severe eating disorders, cancer, AIDS, and conditions that affect the body's ability to absorb nutrients, may also cause Wernicke-Korsakoff syndrome.

Some symptoms of Wernicke's encephalopathy include:

  • confusion and disorientation that continue well beyond the period of drunkenness
  • malnourishment that may cause significant weight loss
  • trouble moving the eyes or strange and jerky eye movements
  • poor balance

Following Wernicke's encephalopathy, the person may develop signs of Korsakoff syndrome. This disorder is a type of dementia.

Symptoms include:

  • memory problems, in particular, difficulties forming new memories
  • poor judgment
  • decreased planning and organizational skills
  • mood and personality changes
  • hallucinations
  • progressively worsening cognitive decline that may affect every area of functioning, including speech, vision, and bowel and bladder function

Vitamin supplements and may reverse symptoms of Wernicke-Korsakoff syndrome within the first 2 years after stopping drinking.

Fetal alcohol syndrome

Fetal alcohol spectrum disorders, which people usually refer to as fetal alcohol syndrome, happen when a developing baby gets exposure to alcohol during gestation. Fetal alcohol syndrome affects many aspects of functioning, and it can cause brain damage.

The symptoms vary in severity, but :

  • intellectual disabilities
  • hyperactivity
  • poor memory
  • trouble concentrating
  • weak coordination
  • vision and hearing issues

Doctors have not yet established a safe level of alcohol consumption during pregnancy, so the best strategy for preventing fetal alcohol syndrome is to abstain altogether from alcohol at this time. If a pregnant woman cannot abstain, she should aim to reduce her alcohol consumption as much as possible.

Head injuries

Alcohol is a risk factor for traumatic brain injuries (TBI) due to falls, car accidents, fights, and other blows to the head. According to a , 35–81% of people who seek treatment for a TBI are intoxicated.

In the short term, a head injury can cause confusion and disorientation. It may also result in dangerous brain swelling. Severe head injuries may even be fatal because they affect the brain's ability to control essential functions, such as breathing and blood pressure.

The long-term effects of head injuries vary but :

  • dementia-like symptoms, such as difficulties forming new memories
  • changes in mood or behavior
  • increased risk of developing Alzheimer's disease and Parkinson's disease
  • changes in blood flow patterns in the brain

Common psychological effects of drinking alcohol include trouble concentrating, mood changes, and depression.

Alcohol has numerous psychological effects, including:

Perhaps the most significant psychological effect, however, is addiction. Over time, people who consume large quantities of alcohol develop a tolerance to the drug. They also become dependent. This dependency means that their brains crave the drug, causing them to experience withdrawal when they do not drink.

Addiction leads a person to continue using alcohol, even when it harms them. People with severe alcohol use disorder may develop a dangerous withdrawal condition called delirium tremens (DT). DT begins with psychological symptoms that include:

Without treatment, DT can be fatal in more than one-third of people whom it affects. People with DT may experience seizures, dangerous changes in blood pressure, and excessive vomiting and diarrhea, which can result in nutritional deficiencies.

Alcohol does more than harm the brain. Both severe intoxication and long-term abuse can damage virtually every system in the body. The physiological :