Effects of Alcohol on the Brain

Robert Gerchalk

Robert is our health care professional reviewer of this website. He worked for many years in mental health and substance abuse facilities in Florida, as well as in home health (medical and psychiatric), and took care of people with medical and addictions problems at The Johns Hopkins Hospital in Baltimore. He has a nursing and business/technology degrees from The Johns Hopkins University.

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Why is America home to 18 million alcoholics? Why is one out of every twelve American adults alcohol dependent? Why do 240 US citizens die every single day from alcohol? Why do more than 9,000 people worldwide die every single day from alcohol? Why is $250 billion spent every year on excessive alcohol consumption?  Why, you may ask, have over 85% of Americans reported having drank at least once in their life? Why is a full quarter of global deaths attributable to alcohol for those between age 20 and 39?

The answer is the human brain.

What we commonly call alcohol, when it comes to drinks, is actually ethanol, one of over fifteen types of alcohol. Ethanol is the type of alcohol inside of adult beverages. As a standalone substance, it is non-addictive. What are addictive are the chemical reactions that happen in our brains when ethanol is consumed.

What’s Up with the Brain?

We must first understand the basics of how the brain operates before we can understand the effects of alcohol. As you may remember from high school, all living things are made up of cells. Brain cells are called neurons. There are over 100 billion neurons in the average human brain. Each neuron is responsible for tens of thousands of different connections, which enable every single thing we do.

The brain is the control room of the body. Every function you can think of is controlled by the brain. Movement, emotions, our five senses, thought, blinking, breathing, heartbeat, pain and pleasure are all controlled by and made possible by the brain. The chemicals responsible for all of this are called neurotransmitters. They deliver messages that tell the body what to do.

There are two basic types of neurotransmitters: inhibitory and excitatory. Inhibitory neurotransmitters slow down overall brain activity, allowing for rest, ease, balance, peace of mind, and general calmness. Excitatory neurotransmitters speed up brain activity, allowing for focus, attention, alertness, possible unease, and nervousness.

Alcohol creates changes in the brain. Three different types of neurotransmitters are affected in particular by alcohol: GABA, dopamine, and endorphins. For non-problematic drinkers and for those just beginning to drink in their lives, alcohol creates pleasurable effects in the brain, which we called being buzzed or drunk. However, excessive drinking over time causes the brain to adapt to these changes.

Eventually, the brain cannot function without alcohol, and we call this alcoholism.

Let’s take a look at how alcohol affects these three neurotransmitters. Then let’s discuss potential brain conditions that are caused by alcohol. Finally, let’s talk about how to treat and/or prevent such alcohol-caused brain conditions.

The Three Neurotransmitters

  1. GABA

Gamma-aminobutyric acid, or GABA, is the brain’s principal inhibitory neurotransmitter. Its main function is to reduce activity in the brain, such as when we are concentrating, sleeping, resting, or attempting to calm down, or even maintaining a normal overall bodily balance. Alcohol increases the flow of GABA inside the brain. If this sounds bad, that’s because it is.

Alcohol-caused increases in GABA explain why drunk people have trouble with their motor skills. Off-balance walking, slurred speech, and poor memory of time spent drinking are all results of increased GABA. Essentially, the overflow causes mild sedation of the brain. This happens every time alcohol is consumed, a GABA increase, and will happen more and more intensely over time, as long as there is drinking.

In response to increased GABA levels, the brain creates more glutamate, an excitatory neurotransmitter. Glutamate counteracts the over-calming effects of GABA. However, the more alcohol one consumes, the more GABA produced, and the more glutamate produced in order to keep the balance. This chemical chain reaction is what causes a tolerance to alcohol.

  1. Dopamine

Most of the entire reward system in our brain is due to dopamine. This neurotransmitter is released whenever we feel pleasure, whether it be from eating, sleeping, having sex, using the bathroom, exacting revenge, lifting weights, scoring the winning shot in your YMCA basketball league, or any other moment we consider pleasurable. Dopamine is released as a reward for pleasure, allowing us to physically feel good when something pleasurable happens. Dopamine, however, has no morals. It’s released in excess by the consumption of alcohol, as well as from most other drugs.

Because some of the initial effects of alcohol are pleasurable, the brain considers alcohol use to be rewarding, and reinforces this by releasing dopamine. Too much dopamine causes an imbalance in the brain, but being the amazing animals that we are, the brain actually adapts to this imbalance, considering it normal. We mentioned this previously. However, with dopamine, there’s more:

Prolonged alcohol abuse physically wears down the brain’s dopamine transporter and receptor sites. Scientists recently conducted a test on brains of deceased alcoholics and consistently found the damage. According to the scientists, long-term drinking will “ultimately interfere with the brain’s ability to use dopamine, and subsequently inhibit the individual’s ability to feel pleasure.”

Repeatedly flooding the brain with dopamine eventually decreases overall dopamine levels. Think of it like over-milking a cow. Eventually the well runs dry. Tolerance builds with increased drinking, but the inability to feel pleasure without dopamine is what actually causes increased drinking.

  1. Endorphins

You may have heard of these pleasure-givers. Endorphins are basically neurotransmitters for nerve cells – they are called neuropeptides. The word ‘endorphin’ is actually a blend of two words: ‘endogenous’ and ‘morphine’. Something endogenous originates from within an organism. Morphine is a strong opioid painkiller. Endorphins are morphine-like molecules produced by the central nervous system, released by the body to counteract physical pain. Endorphin release can also create a feeling of euphoria.

Endorphins are produced naturally in response to pain, but are also produced by human activities such as working out and laughing. Alcohol abuse also releases endorphins. Different parts of the brain release endorphins according to different responses, and alcohol releases endorphins in two different parts: the nucleus accumbens and the orbitofrontal cortex, which control addictive behavior and decision-making, respectively.

With so many neurotransmitters being released when we drink, along with endorphins, it’s almost no wonder alcohol is so addictive. Not only does alcohol trick the brain into thinking that drunk is the normal way to be, alcohol also releases several pleasure-inducing chemicals. The brain becomes used to this rush of pleasure, and problematic drinking begins its course.

When alcoholics stop drinking, the increased GABA, glutamate, and dopamine levels cause withdrawal symptoms, such as hallucinations, tremors, convulsions, and even delirium tremens, a condition lasting 2-3 days which includes shaking, shivering, irregular heartbeat, sweating, high body temperature and/or seizures.

Alcohol is addictive because the brain becomes used to it in order to function properly. The neurotransmitters and endorphins reward the brain for drinking. There is a cruel irony here… we are being ‘rewarded’ for creating potential brain conditions and/or illnesses.

Brain Damage from Alcohol

Aside from being addictive due to brain changes, excessive drinking can lead to several different brain diseases or conditions. We will leave out the obvious: fatigue, hangover, headache, dehydration, irritability, slurred speech, blurry vision, slower reactions… It’s obvious that alcohol affects the brain. It’s scary just how much.

Alcohol Withdrawal Syndrome

If you are an alcoholic, your brain has become completely used to the presence of alcohol. Stop drinking all of a sudden and you are at risk for alcohol withdrawal syndrome, or AWS. Also, anyone who drinks heavily for an extended period of time and then stops altogether is at risk for AWS. Symptoms are plenty, and if severe, a medical emergency is at hand. About half of those at risk will become affected.

Symptoms of AWS include nausea, vomiting, headache, sweating, anxiety, tremors, sleeplessness, nightmares, increased heart rate and high blood pressure. Severe symptoms include heavy confusion, extreme irritability, fever, hallucinations, and in the most dangerous cases, seizures. Delirium tremens, known as DT, can be deadly, and consists of full body convulsions.

Wernicke-Korsakoff Syndrome

WKS occurs most often among alcoholics, and encompasses two closely related conditions: Wernicke’s encephalopathy (WE) and Korsakoff’s syndrome. WE consists of lesions in the central nervous system, causing ataxia, paralysis of eye muscles, and overall confusion. Korsakoff’s syndrome consists of a lack of vitamin B1 in the brain, caused by alcohol abuse. Symptoms include severe memory loss, inability to form new memories, confabulation (inventing memories), and apathy. Both WE and Korsakoff’s syndrome are neurological disorders.

The two often co-occur in alcoholics, and together form WKS, a memory-impairing, vision-affecting, seizure-causing brain disorder. The more one drinks, the more at risk they are. WKS is a multi-symptom form of amnesia, and up to 2% of the population is afflicted. This may seem low, but 2% of America is almost six and a half million people.


Swelling of the brain, or neuroinflammation, can occur from many things. Infection, injury, aging, and toxic metabolites are among the causes. When alcohol is metabolized by the liver, a chemical called acetaldehyde is left over. Acetaldehyde is a toxic metabolite, so harmful that it can cause cancer.

Neuroinflammation is one of the primary causes of Parkinson’s disease, and can cause a multitude of other issues, including Alzheimer’s and multiple sclerosis. Excessive drinking can cause neuroinflammation by creating too much acetaldehyde.

Impaired Development in Minors

A study done by the University of Eastern Finland shows that alcohol dramatically impairs brain development in teenagers. “The maturation of the brain is still ongoing in adolescence and until the twenties. Our findings strongly indicate that alcohol use may disrupt this maturation process,” said Noora Heikkinen, lead researcher.

This is a problem, considering up to 20% of Americans aged 12 to 20 reported themselves as drinkers in the 2015 National Survey on Drug Use and Health. Underage alcohol abuse can cause schizophrenia, OCD, depression, bipolar disorder, PTSD, autism, and damage to the insular cortex, a part of the brain responsible for perception and motor control among other things.

Underage alcohol abuse can also cause increased levels of GABA, or gamma-aminobutyric acid, in teens. High GABA levels can cause shortness of breath, high blood pressure, increased heartrate, and night terrors, among other disorders. Yet another disorder caused by underage drinking is cortical thinning. This is when the cerebral cortex loses mass, causing a reduction is cognitive ability. Normally, cortical thinning only occurs with old age.

Alcoholic polyneuropathy

Also known as “alcohol leg,” polyneuropathy is a brain disorder which causes nerves throughout the body to function improperly, causing loss of mobility. Paresthesias, or feeling pain without cause, also occurs with alcoholic polyneuropathy. In its early stages, alcohol leg is reversible, but in mild to severe cases it could be permanent.

Liver-related Brain Disorders

Hepatic encephalopathy, also known as HE, can occur as a result of severe alcoholic hepatitis, a disease caused by heavy drinking. Symptoms include extreme confusion, altered levels of consciousness, coma, and even death. Treatment includes removal of toxins directly from the intestines.

Also, liver cancer can cause severe brain disorder, and can be caused by heavy drinking when cirrhosis is occurring.

In Conclusion

Alcohol causes an absolute plethora of brain disorders, diseases and damage types. Please drink responsibly. If you are alcohol-dependent, or feeling like you’re close, please seek professional treatment today.