Some of the effects, like slurred speech and loss of balance, can be very obvious. Others, like cell death, not so much.

Amanda MacMillan
April 24, 2018

A glass of wine with dinner, a happy-hour beer after work, a cocktail (or three) on vacation: Alcohol is deeply ingrained in American culture, and, for many of us, it’s a normal part of our daily lives.

Studies suggest that alcohol, when consumed at low to moderate levels, may have some health benefits. It can also produce feel-good effects, which is why many of us turn to it in social situations or during stressful times.

But the research is also clear about something else: When a person consumes alcohol above and beyond moderate levels, it can have damaging effects on the body and on the brain—both short-term and permanently. Some of those effects, like slurred speech and diminished memory, can be quite clear; others, like long-term cellular damage, may not be as obvious.

If you’ve ever wondered what’s really going on in the brain when a person’s had too much to drink, here’s a brief primer. The experts we spoke with agree: Most people shouldn’t feel guilty about enjoying the occasional drink—but keep these effects in mind if you’re tempted to overdo it.

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Short-term effects of alcohol on the brain

Drinking alcohol alters the levels of neurotransmitters in the brain, says Maria Pagano, PhD, addiction researcher and associate professor of psychiatry at Case Western Reserve University School of Medicine. These chemical messengers transmit signals throughout the body and play a large role in controlling behavior, emotion, and physical activity.

“For starters, alcohol slows down the neurotransmitter GABA, and that’s what drives the sluggish movement, slurred speech, and slower reaction time in someone who’s intoxicated,” Pagano says.

At the same time, she adds, alcohol speeds up a neurotransmitter called glutamate, which is responsible for regulating dopamine in the brain’s reward center. “It’s generating feelings of pleasure and well-being,” says Pagano. “That’s why you might get that warm, fuzzy feeling when you’re drinking.”

Alcohol lowers inhibitions and clouds judgment, as well, which could lead a person to engage in risky behaviors like having unprotected sex or driving a car while drunk. And if a person has an underlying mental health disorder, like depression or bipolar disorder, it can exacerbate symptoms and increase mood swings.

Binge drinking also affects the cerebellum (which helps regulate balance) and the cerebral cortex (which is responsible for taking in and processing new information). When these regions of the brain are slowed down, a person might feel dizzy and stagger when walking, have blurred or double vision, and have difficulty paying attention to things going on around them. “Your sensory uptake has been dulled, so you’re not going to be taking in new information as well,” says Pagano.

The brain’s hippocampus region—which helps create new memories—is also affected by alcohol, which contributes to blackouts and short-term memory lapses while drinking. Studies suggest that men and women experience alcohol-induced blackouts at equal rates, even though women tend to drink less often and less heavily than men.

In the most extreme cases, drinking too much, too fast can cause a loss of consciousness. “We worry about that for safety reasons, of course, but this is also a sign of cell death,” says Lara Ray, PhD, professor of psychology at the University of California Los Angeles Brain Research Institute. “So we also worry about brain damage—and with multiple episodes of heavy drinking, that damage can have long-term consequences for learning and memory.”

Most of these effects are caused by a spike in blood-alcohol content over a short period of time, says Ray. Taking breaks between drinks—and being sure not to imbibe on an empty stomach—can help reduce your risk of experiencing them yourself.

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Long-term effects of alcohol on the brain

Binge drinking can certainly put you at risk for embarrassment, injury, or poor decisions with lasting consequences. But if you make it through a wild night with nothing worse than a hangover, you may think you’re in the clear. Unfortunately, if heavy drinking becomes a regular thing, that’s not the case.

According to a 2008 study in the Archives of Neurology, heavy drinking over a long period of time seems to actually shrink brain volume. The study found that people who had more than 14 drinks per week over a 20-year timeframe had 1.6% smaller brains (a measure of brain aging) than those who were non-drinkers. Overall, the association was slightly stronger in women than in men.

Heavy drinking also may speed up memory loss in early old age, at least in men, according to a 2014 study in the journal Neurology. Men in the study who had more than two and a half drinks a day experienced signs of cognitive decline up to six years earlier than those who did not drink, had quit drinking, or were light or moderate drinkers. (Results for women were not conclusive, the authors say.)

People who drink regularly may also notice that booze doesn’t have the same effect on them as it used to. “With chronic drinking, the wiring element to your brain’s reward system can get worn out and lose some of its normal functioning,” says Pagano. “You build up a tolerance, and after a while you don’t feel as good as you once did with the same amounts of alcohol.”

These changes in the brain also cause people to change their behaviors around alcohol. “They become much more likely to seek alcohol, and to rely on it to cope with negative feelings,” says Ray. “Often when people start drinking, they drink to feel good—but as they drink more chronically, they have to drink to avoid feeling bad.”

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That leads to higher and higher levels of consumption, which can cause greater damage to the brain and the rest of the body. Alcohol kills cells and damages cellular networks in the brain, for example, and it’s not entirely clear to what extent they can grow back.

“You might hear the classic term ‘wet brain,’ and that’s a real thing,” says Pagano. “Wet brain” is technically known as Wernicke-Korsakoff syndrome, and it’s a type of dementia caused by a deficiency of thiamine, or vitamin B1, in the brain. Alcohol hinders a person’s absorption of thiamine, and interferes with the enzyme that converts it into a usable form in the body.

“Chronic drinking can really alter a person’s personality,” says Pagano. “I’ve seen cases where I wouldn’t recognize a patient based on how they’re acting.” Brain damage (and symptoms like brain fog) can also be caused by cirrhosis of the liver, another common complication of long-term, heavy drinking.

After cutting back on alcohol, Pagano says, damaged regions of the brain can start to “light up” again on brain scans. “But there are certainly limits,” she says, “and we often see improvement only after months of complete abstinence and giving the brain time to heal.”

Alcohol-related damage to the brain (and the body) can even be deadly: In a recent Lancet study, people who regularly had 10 or more drinks a week had one to two years shorter life expectancies than those who had fewer than five drinks a week.

That number jumped to four or five years for those who had 18 drinks or more per week. The researchers observed that alcohol consumption was linked to various types of cardiovascular problems, including stroke—a potentially fatal blockage of blood flow to the brain.

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How much is too much?

Whether or not a person engages in drinking should be a decision they make on their own, or with the help of a doctor or mental health professional. For many people without a history of dependence or addiction, Pagano says, drinking at low or moderate levels—no more than seven drinks a week for women, and no more than 14 a week for men—can be a perfectly healthy part of life.

But if you have a response to alcohol that’s noticeably different from other people’s, it may be time to reexamine your relationship with drinking, says Pagano. “If you can drink other people under the table, or you see your friends leaving alcohol in their glasses and you know you could never do that yourself, those are signals you’ve got a genetic setup for developing an addiction,” she says.

Ray agrees that some people can safely stay within the guidelines for low-risk drinking, while others—because of genetics, stressful life situations, or other risk factors—may have a hard time sticking to those limits. That’s important to keep in mind, she says, as researchers have observed an increased prevalence of alcohol-use disorders and heavy drinking in recent years, primarily among women.

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While alcohol can act as a social lubricant and may provide “liquid courage” for people who are otherwise anxious or shy, Pagano warns against relying on it too much. “If drinking allows you to engage in behavior you wouldn’t engage in otherwise, maybe you shouldn’t be doing it,” she says. “And if you always use it to have a good time, you won’t learn how to be okay in social situations without it.”

For people who do decide to stop drinking, Pagano says there are many reasons to be optimistic. “A lot of people fear giving it up and not being able to drink,” she says. “But in reality, life can get better when you’re making better choices and you’re able to fully savor your experiences, rather than seeing them through a haze.”