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  • Writer's pictureKim May

Your brain and body on alcohol

"Love makes the world go round? Not at all. Whiskey makes it go round twice as fast.”

~ Compton Mackenzie

We know how we feel when we drink, but how well do we understand the mysterious alchemy which is taking place?

Why might we feel more relaxed? Why might we be interested in stealing traffic cones? Why is there vomit on my refrigerator?

Depending on your relationship with alcohol, you might have more serious and worrisome questions, like what are the effects of alcohol on my brain and body and are they permanent? Or why is it feeling hard not to drink?

Let’s start getting you some answers.

Bottoms up

Once consumed, alcohol is quickly absorbed into the body. It passes through the digestive tract and is absorbed into the bloodstream through the intestines, then passes the liver before making its way to the brain.

However, our first drink skips the visit to the intestine, meaning there is a much more rapid effect when drinking on an empty stomach.

Whether or not we have food in our stomachs when we drink is generally the most powerful influence on alcohol absorption. On an empty stomach, the blood absorbs the alcohol quickly, reaching peak concentration in about an hour; however, alcohol consumed with food would take about two hours.

Rapid absorption of high concentrations can be medically serious, suppressing the central nervous system which can cause death. For this reason, binge drinking and drinking games are particularly dangerous.

Although there are all sorts of individual differences when it comes to how we handle alcohol, our body type determines alcohol distribution. The more fat and muscle a person have, the more fat and muscle there is to absorb the alcohol, leading to a lower alcohol level than a smaller person who drank the same amount. Extra weight also slows the elimination of alcohol, so larger people tend to retain it longer.

However, for all of us, the rate of alcohol metabolism is constant—when we drink more than we can metabolize efficiently our system becomes saturated and the “extra” alcohol accumulates in our blood and body tissues. This results in higher blood alcohol concentrations and greater intoxication.

Alcohol and the brain

Alcohol is classified as a sedative drug because alcohol has an inhibitory effect on nerve cells. People are confused by this, reporting they often feel excited or stimulated when they drink.

Yes, alcohol is a sneaky little minx.

There is a biphasic action to alcohol. At low concentrations (the good buzz), alcohol does stimulate (rather than inhibit) some nerve cells. However, as we drink more and alcohol concentration increases, those cells decrease their firing rates, and their activity slows or becomes suppressed.

GABA, Glutamate, and Dopamine

GABA and glutamate, and dopamine are neurotransmitters in the brain. GABA is referred to as the “brain’s sedative” and this is compounded by alcohol. Glutamate is excitatory, but alcohol suppresses that. It is believed that the enhancement of GABA activity is responsible for the sedating effects of alcohol. The suppression of glutamate may lead to the inability to form new memories or think in complex ways. Additionally the inhibition of the glutamate receptor function causes muscular relaxation, discoordination, slurred speech and staggering.

Dopamine is the transmitter responsible for the rewarding effects of substances (alcohol, cocaine, etc.) and actions (sex, gambling, etc.), the positive reinforcement of pleasurable feelings. Where alcohol is concerned, the dopamine activity occurs while blood alcohol concentration is rising, not falling. So, we get an initial dopamine rush, but this disappears relatively quickly, but we often continue to “chase the high.” Interestingly, anticipation of drinking can increase dopamine activity, which can increase the motivation for drinking on a particular day as well as across time.

Wanting more than actually liking can be a precursor to a substance use disorder.


Remember that earlier question of why someone might be inclined to steal a traffic cone while under the influence? Well, the answer is disinhibition, or in laymen’s terms, acting a fool. Most of us restrain our behavior most of the time. Therefore, we do not run around punching our boss and taking off our clothes at the grocery store. We are restrained by values, laws, rules, perception of consequences, etc. However, the frontal cortex, responsible for judgment and planning is depressed by even low doses of alcohol. While alcohol is depressing the frontal cortex, the rest of our brain is raring to go.

This translates to being more impulsive and often making poor choices.

Alcohol and the body

Large doses of alcohol, especially on a regular basis, can cause toxicity in the body. The reason alcohol is toxic is due to its own molecular effects on tissues. When our body is breaking down alcohol, we produce a break down product called acetaldehyde, which is even more toxic, but fortunately our liver breaks it down quickly. However, the breakdown occurs at a steady rate, so if we consume faster than the breakdown can occur, the longer the ethanol and acetaldehyde are in the tissues causing damage.

Very few of us have tangled with alcohol and not been subjected to some amount of vomiting. There are two effects of alcohol that make people feel like vomiting.

One is the direct effect alcohol has on the stomach lining. Alcohol can act as a poison, causing a series of events that cause the body to rid itself of the toxin. Secondly, alcohol has a direct effect on the vomiting (emetic) center of the brain stem to stimulate vomiting. It is worth noting that people differ greatly in their sensitivity to these effects.

Long-term effects of alcohol on the brain and body

To date, there are five areas of mental ability that are found to be compromised due to chronic alcohol abuse. It is important to note that not all people with an alcohol use disorder (AUD) will develop these issues.

1. Making memories. It is believed that alcohol related damage to the hippocampus, the mammillary bodies and/or the frontal lobes may cause problems in creating new memories. Meaning, a person may well remember the periodic table, but not the movie they watched yesterday afternoon.

2. Problem solving. Mental flexibility is being able to switch strategies and approaches to problems. Often, people who are considered “chronic drinkers” frequently get stuck modes of problem-solving and take longer to arrive at a solution. This is likely the effects of long-term alcohol use on the executive functioning that occurs in the frontal lobes.

3. Focus. Placed in more novel or challenging situations, people may experience difficulties focusing their attention and maintaining concentration.

4. Abstract thinking. Being able to think in ways that are not directly tied to concrete things. For example, concrete knowledge is what gum is and what you do with it. Abstract thinking would be producing different ways to use gum.

5. Perception of emotions. Chronic, heavy drinking can interfere with the ability to perceive emotion in language. Subtleties like tone that convey how people are feeling are often missed.

The good news is that people do seem to regain these abilities at least partially. However, it is worth noting that even social drinkers, depending on their consumption may be at risk of developing those long-term effects. Pattern becomes highly relevant here—someone who drinks one beer 7 days a week is not terribly likely to be affected, whereas someone who has seven drinks on Friday might be.

Possible health concerns that long term alcohol consumption can cause include fatty liver, alcoholic hepatitis, cirrhosis, gastritis, Wernicke-Korsakoff syndrome, mild hypertension, pancreatitis, cardiomyopathy, esophageal varices, and may increase the risk of certain types of cancers. (Please see your doctor ASAP if you have any medical concerns regarding your drinking).

With regards to mental health, drinking can cause or exacerbate both depression and anxiety.

Am I drinking too much?

Good question. Complex question.

Let’s talk about your tolerance, meaning that after continued drinking over time, you now need a higher amount to get the SAME effect. Tolerance is an indicator that alcohol exposure has changed your brain. As tolerance goes up, so does the chance for developing (or worsening) alcohol use disorder.

Also, just because feel like you can handle elevated levels of alcohol, does not mean your brain and body are not worse for wear. Your brain might need more alcohol to give you the high you want, but your liver and other organs do not develop a tolerance.

Although self-diagnosing is not typically a good idea, you can read the diagnostic criteria for alcohol use disorder here. However, wherever you are on the continuum of use, you may feel that your drinking is causing you some problems. It is a dangerous myth that one needs to “hit rock bottom” before a change can be made.

If you need support, Substance Use Therapy is here. You may want to examine your use, begin making changes, or need help with additional resources and referrals.

Whatever you are facing, you do not have to face it alone.


Anderson, K. (2010). How to Change Your Drinking. HAMS Harm Reduction Network.

Denning, P., & Little, J. (2017). Over the Influence: The Harm Reduction Guide to Controlling Your Drug and Alcohol Use. The Guilford Press.

Erickson, C.K. (2007). The Science of Addiction. W.W. Norton & Company.

Kuhn, C., Swartzwelder, S., & Wilson, W. (2019). Buzzed: The Straight Facts about the Most Used and Abused Drugs from Alcohol to Ecstasy. W.W. Norton & Company.

About the Author:

Kimberly May, LPC-S, LMFT is a therapist at Substance Use Therapy in Austin, TX. Kimberly works with individuals, couples and families whose lives have been affected by substance use. By utilizing a harm reduction framework, Kimberly works effectively with people in any stage of use. In addition to substance use, she works with other issues such as anger, burn-out, anxiety and grief. Contact today to schedule a no-charge, 30 minute, in-person consultation. *Note: telephone and telehealth sessions are currently available.

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