How does alcohol affect the brain?

Most moderate drinkers are well aware of—and likely enjoy—the way alcohol makes them feel, including cheerful, relaxed and outgoing. The question that some may not want to ask is: What is the true impact of these feelings via alcohol on your brain?

This was one of the recent topics of the Ohio State Gray Matters podcast, which features neurological experts answering questions from patients about brain health.

John Corrigan, PhD, a professor in the Department of Physical Medicine and Rehabilitation and interim director of the Ross Center for Brain Health and Performance at Ohio State, researches drinking and what it does to you.

How much drinking is too much?

Corrigan says having a “few drinks” is not harmful to most people, but most people fail to recognize what qualifies as “a few.” He says to follow this guideline:

For women: Not more than three drinks a day and seven per week.

For men: Not more than four drinks a day and 14 drinks per week.

“Women and older adults have less total mass in their body, including water. So there’s less dilution of the toxins in alcohol. As a result, less alcohol has more of an effect,” says Corrigan.

Those limits may seem to contrast with behaviors you observe from the average person at your local bar or restaurant, but Corrigan says there’s a reason for that.

“We as a society are drinking more alcohol than is recommended. We tend to look around us and think it’s typical to drink four to five a night, but it’s not.”

What are the effects of alcohol on the brain (short term)?

Alcohol affects any parts of the body, including the brain, that are big users of glucose, says Corrigan.

Glucose is one of the key elements that we metabolize for energy for the brain. One area specifically within the brain that uses a lot of glucose is the cerebellum in the back of your head. This area of the brain is very involved in balance and fine motor function. So it’s no surprise as you get intoxicated that your balance is disrupted and you get a bit clumsy in the fingers.

Another area of the brain affected by alcohol is the hippocampus, which is central to forming both short- and long-term memories.

“Thus, people who drink too much report having blackouts—periods  of the night where they don’t remember what happened even though functioning and awake,” says Corrigan.

Finally, alcohol affects the system of the brain involved in regulating dopamine, a compound in the brain that tells us what we should or should not do. As you become intoxicated, those particular ‘no-go’ aspects of inappropriate behaviors are undermined.

What are the effects of alcohol on the brain (long term)?

Ohio State brain experts say the long-term effects of excessive drinking can be damaging and irreversible.

Over time, you may notice your sense of balance deteriorating. That may not be a problem at 30, 40 or 50, but it becomes more impactful as you enter your senior years.  

Beyond balance, your brain also can experience other long-term problems from alcohol.

Zachary Weil, PhD, assistant professor in the Department of Neuroscience at Ohio State Neurological Institute, is an expert on traumatic brain injury (TBI). He says alcohol and TBI are intertwined issues that are difficult to separate.

“In our research, we gave mice mild head injuries—so mild there would be no noticeable effects after one hour—early  in life and looked at the impact of drinking as they aged,” Weil says.  

“Those animals tended drink two to three times as much alcohol compared to uninjured animals,” he adds.  

Why is this happening?

In essence, Weil says, those animals with a previous injury find alcohol more rewarding than animals without injury. He says the concern is the vicious cycle this can have on those suffering with TBI or who drink excessively.

“You drink too much so you’re more susceptible to injury, so you drink and so on,” he says.

The final advice from these brain doctors?

“My feeling is, we keep compromising the brain. My recommendation would be, be cautious,” says Corrigan.

Gray Matters Podcast

You can learn more about cutting-edge brain research underway at Ohio State and beyond by downloading the Gray Matters Brain Health podcast.