How Does Alcohol Affect the Brain?

How does alcohol affect the brain? Short-term effects of alcohol include diminished memory and slurred speech. Long-term cellular damage, in contrast, may not be as obvious. Alcohol-related brain impairment (ARBI) is long-term brain damage that kills brain cells and impairs memory.

Drinking in moderation is defined as one or fewer drinks per day for females and two or fewer drinks per day for males. Heavy drinking for females is eight or more drinks per week and 15 or more drinks per week for males.

Research has shown that there's no safe level of alcohol consumption. Even low levels of alcohol consumption can harm your health, and high levels have even worse effects. Read on to learn how alcohol affects the brain in the short- and long-term.

What Does Alcohol Do to Your Body?

People who drink regularly may notice that alcohol does not have the same effect on them as it used to. You build up a tolerance over time and do not feel as good as you once did with the same amount of alcohol. High alcohol consumption can damage your brain and the rest of your body.

Drinking alcohol alters the levels of neurotransmitters in your brain. These chemical messengers transmit signals throughout your body and control behavior, emotion, and physical activity.

Alcohol increases the effects of gamma-aminobutyric acid (GABA), for example. This causes sluggish movement, slurred speech, and slow reaction time when you are drunk. Alcohol also decreases the effects of glutamate, which regulates dopamine in your brain's reward center. This generates feelings of pleasure, causing a warm, fuzzy feeling.

Alcohol lowers inhibitions and clouds judgment, which may lead you to engage in risky behaviors. Research has shown that alcohol can exacerbate symptoms and mood changes in people with mental health disorders like depression or bipolar disorder.

Does Alcohol Kill Brain Cells?

Alcohol kills cells and damages cellular networks in the brain. Heavy drinking alters nerve cells and makes them smaller than normal, which can have severe, lasting effects on your brain. It's not entirely clear to what extent brain cells can grow back.

How Does Heavy Drinking Affect the Brain Long-Term?

A study published in 2021 found that heavy drinking may lead to loss of brain volume. The researchers noted that people with alcohol use disorder (AUD) had less brain matter than others. The affected brain regions controlled skills like attention, language, memory, and reasoning. Alcohol can, therefore, lead to worse memory and impaired judgments, among other changes.

Cirrhosis may also cause brain damage. This complication of long-term heavy drinking causes scarring of the liver. Scar tissue impairs the liver's ability to create proteins, filter the blood, and other bodily functions.

Damaged regions of the brain can start to "light up" on brain scans after you cut back on drinking, but there are limits. It may take several months of complete abstinence from alcohol to give your brain time to heal.

ARBI can be deadly. In a study published in 2018, people who regularly had 10 or more drinks per week had one to two years shorter life expectancies than those who had fewer than five drinks. That number increased to four or five years shorter for people who had 18 drinks or more per week. The researchers linked alcohol consumption to various types of cardiovascular problems, including stroke.

Disorders Linked With ARBI

The effects of heavy drinking on the brain can range from mild to severe. Health conditions that are linked to ARBI include:

• Cerebellar degeneration: This disorder causes nerve cells in the cerebellum to die. The cerebellum is the part of your brain that controls balance and coordination. Symptoms include slurred speech and unsteady movements.
• Frontal lobe dysfunction: The frontal lobe of your brain controls social behavior. Damage to the frontal lobe may cause changes in behavior and personality.
• Hepatic encephalopathy: This is brain damage that occurs as a result of cirrhosis.
• Peripheral neuropathy: This type of nerve damage causes muscle weakness, numbness, and pain.
• Wernicke-Korsakoff syndrome (WKS): This type of dementia, commonly known as "wet brain," is caused by a thiamine (vitamin B1) deficiency in the brain. Alcohol hinders the absorption of thiamine and interferes with the enzyme that converts it into a usable form in the body.

Alcohol and Memory Loss 

Alcohol has short- and long-term effects on your memory. Heavy drinking slows the cerebral cortex, which takes in and processes new information in your brain. You might have difficulty paying attention. Alcohol also dulls sensory uptake, so it might be difficult to take in new information.

Alcohol affects the hippocampus, which helps create new memories, in your brain. This contributes to blackouts and short-term memory lapses when drinking. Research has shown that men and women experience alcohol-induced blackouts at equal rates, although women drink less often and heavily than men.

Multiple episodes of heavy drinking can have long-term consequences for memory. A study published in 2014 found that heavy drinking can speed up memory loss in early old age in men. The researchers noted that men who had more than 2.5 drinks per day showed signs of cognitive decline up to six years earlier than those who did not drink, quit drinking, or were light-to-moderate drinkers. The results for women were inconclusive.

How Does Alcohol Affect Brain Development?

Adolescents are more susceptible to brain damage from alcohol use than adults. Teenagers are likely to engage in high-risk behaviors, such as driving under the influence and using other substances. Blackouts, which impact short-term memory, are also common among adolescents.

Heavy drinking can impair brain development in adolescents. Underage drinking increases the risk of anxiety, depression, and low self-esteem, which can affect the brain long-term. Heavy drinking may weaken parts of the brain that are responsible for cognitive function and emotion regulation.

How Much Is Too Much?

Drinking at low or moderate levels can be part of a healthy lifestyle. This is no more than seven drinks per week for females and no more than 14 per week for males. Some people can safely stay within this recommendation for low-risk drinking.

Others may have a hard time sticking to this limit due to genetics, stress, and other risk factors. Research has found an increased prevalence of AUD and heavy drinking, primarily among women. Talk to a healthcare provider if you have a history of addiction or dependence.

Avoid alcohol altogether if you are:

• Going to drive a vehicle or operate machinery
• Managing a health condition that could be made worse by drinking alcohol
• Participating in activities that require skill, coordination, or alertness
• Pregnant or think you might be pregnant
• Recovering from AUD
• Taking medications that interact with alcohol
• Younger than the legal drinking age of 21

Alcohol can act as a social lubricant and provide "liquid courage" for people who are anxious or shy, but do not rely on it too much. You may want to avoid or limit alcohol if it allows you to engage in behaviors you would not normally engage in.

A Quick Review

Alcohol can be tricky. It's legal if you are 21 or older, and it's often used in social situations. Alcohol, however, can negatively affect your brain if you use it in excess or certain situations. Contact a healthcare provider or call the Substance Abuse and Mental Health Services Administration (SAMHSA) national helpline at 1-800-662-HELP (4357) if you feel alcohol is interfering with your life or health.

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