How does alcohol affect the brain and central nervous system?
How does alcohol affect the brain? Alcohol is a drug that slows the central nervous system, and with heavy use over months and years, it changes the way the brain looks and works. The damage is cumulative, and it tends to show up in memory first.
Alcohol turns up the brain’s main calming signal, known as gamma-aminobutyric acid, or GABA, and turns down its main stimulating signal, glutamate. That is why the first drink of the evening feels like relief, and it is also why the brain pushes back.
For many people who drink heavily, the more pressing question is not what alcohol does to the brain. It is whether the damage can be undone.
Fortunately, much of it can. In this article, Dr. Leeds explains what alcohol does to the brain, and the safest way to keep the damage from going any further.
Why is memory the first thing to go?
Memory is one of the higher functions of the brain, and it is among the first to show the strain of heavy drinking.
After a night of heavy drinking, you may forget small details of the evening, or you could have a full blackout, where hours are missing. A blackout is not the same as passing out. You were awake, walking and talking, while alcohol temporarily blocked the transfer of new memories into long-term storage.
So, was the memory of that night lost? No. It was never recorded, as explained in a separate article about alcohol blackouts and memory loss.
While a single blackout is temporary, years of heavy drinking can wear down both short-term and long-term memory. Often, family members notice before the person who is drinking does.
Does alcohol kill brain cells?
This is a good question. The answer is yes and no. The old schoolyard claim, that every night of drinking kills off millions of brain cells, is not how the damage happens. If it were, a few decades of weekends would leave a person with no brain at all.
Yet, years of heavy drinking do leave the brain smaller. Nerve cells, or neurons, shrink and lose some of the branching connections that they use to communicate with one another. Some neurons can be lost as well, most clearly in the frontal lobes, which handle judgment and planning, and in the cerebellum, which manages balance.
So, does one night of drinking kill millions of brain cells? No. Do years of heavy drinking shrink the brain? Yes. Is the shrinkage permanent? Much of it is not.
Thiamine deficiency injures the brain in its own way.
People who drink heavily often eat poorly, and the gut absorbs less thiamine, also known as vitamin B1, from the food that they do eat. A severe lack of thiamine can lead to Wernicke encephalopathy, a brain emergency marked by confusion, loss of coordination, and abnormal eye movements. It calls for emergency care.
Prompt treatment with thiamine can reverse some of it. Without treatment, it can progress to Korsakoff syndrome, a severe and lasting loss of memory, and the two together are known as Wernicke-Korsakoff syndrome, or by the unkind street name, “wet brain.”
To be clear, Wernicke-Korsakoff syndrome is not caused by quitting alcohol. It is caused by a vitamin deficiency that builds during the drinking, which is why, in medicine, we give thiamine to patients who drink heavily.
Can weekend binge drinking cause long-term brain problems?
There are people who believe they do not have a drinking problem because they only drink on weekends, or maybe once every month or two. The problem is that if they binge drink on those occasions, the damage still adds up.
There is a category of drinker known as the gray area drinker, a person who does not drink every day and has not had serious consequences from drinking. While gray area drinkers often believe that they do not have a problem at all, their occasional heavy drinking still counts toward the total. The brain does not check the calendar.
There is no amount of alcohol that is good for the brain, and heavy drinking weakens the immune system as well. Gray area drinking can also progress to alcohol use disorder. If you see yourself in this section, it is not a bad idea to read about gray area drinking and the Sinclair Method. The sooner the drinking comes down, the better.
Why is drinking harder on a brain that is still developing?
The human brain is not finished at 18, or at 21. It keeps developing into the mid-20s, and the last areas to mature are the frontal areas involved in planning, judgment, and decision-making.
Part of that late work is myelin, a sheath of fatty material and protein that wraps around nerve fibers, much like the insulation around a hot water pipe. An insulated nerve fiber carries its signal faster and more reliably.
Heavy drinking before that work is complete can alter the way the brain develops, and some of the change may be lasting. Dr. Leeds once heard a talk given by a young man who had overcome a serious addiction that began in high school. He told the audience that it had cost him many points of intelligence, but, fortunately, he had the points to lose.
Most of us do not have points to spare. If you are a parent, explaining this to a teenager may do more good than simply telling them not to drink.
Why does alcohol calm anxiety at night and make it worse the next morning?
Many people with social anxiety have discovered that a drink or two takes away the fear of a crowded room. Yet, the next morning, they wake with a pounding heart and a sense of dread that is worse than the anxiety they started with. Some people call it “hangxiety.”
Does alcohol relieve anxiety, or does it cause anxiety? Both. While you are drinking, the brain adjusts to the calming effect, and when the alcohol wears off, you are left more restless and anxious than you were before the first drink.
There is no cure for hangover anxiety other than time. The trouble is that another drink also works, for a few hours. This cycle, more than the anxiety itself, is what walks many people into alcohol use disorder.
Unfortunately, when a person with anxiety does see a doctor, the visit too often ends with nothing more than a prescription. And, if you drink heavily every day, the anxiety and shaking hands that come from not drinking are not a hangover. They are early withdrawal.
Stopping suddenly is the dangerous part.
Some drugs have withdrawal syndromes that are miserable, but not physically dangerous. Alcohol is not one of them. After months or years of daily heavy drinking, the nervous system has adapted to alcohol, and when the alcohol is suddenly taken away, the brain is left overexcited with nothing to calm it.
The first symptoms, which can begin within hours of the last drink, are tremor, sweating, anxiety, nausea, and insomnia. Seizures are most common in the first two days. Delirium tremens, known as the DTs, most often appears two to four days after the last drink, with severe confusion, agitation, hallucinations, fever, and a racing heart.
Delirium tremens is a medical emergency, and it can be fatal. If you drink heavily every day, quitting cold turkey on your own is not safe and not worth the risk. The safe way to stop is with a doctor involved from the first day.
Call 911 or go to the nearest emergency room if a person who has recently stopped or cut back on drinking:
- has a seizure
- becomes confused or does not know where they are
- sees, hears, or feels things that are not there
- has a fever, a racing or irregular heartbeat, or severe shaking
- cannot keep fluids down or cannot be woken
If you are having thoughts of suicide, call or text 988, the Suicide and Crisis Lifeline, at any hour.
Benzodiazepines protect the brain during alcohol withdrawal, but only for a few days.
In a medically supervised withdrawal, doctors often use a benzodiazepine, such as Librium (chlordiazepoxide), Ativan (lorazepam), or Valium (diazepam), to prevent seizures and delirium tremens. Used for a few days and then tapered off, these medications protect the brain through a dangerous week.
Unfortunately, the prescription does not always end there. Is a benzodiazepine just alcohol in a pill, as some rehab staff describe it? They are not entirely wrong. Yet, the problem with long-term use goes beyond replacing one drug with another.
In September 2020, the US Food and Drug Administration, or FDA, required an updated boxed warning on every benzodiazepine. The updated labels state that physical dependence can occur when these medications are taken steadily for several days to weeks, even as prescribed, and that in some patients, withdrawal symptoms have lasted from weeks to more than 12 months.
While the worst of alcohol withdrawal usually passes within days, benzodiazepine withdrawal, for some people, lasts far longer, and patients often describe it as an injury to the nervous system that is worse than the alcohol withdrawal it was meant to prevent. A person who became dependent on a prescribed benzodiazepine is typically not addicted. Physical dependence is not addiction. It is a medical condition, and it calls for a slow, patient-directed benzodiazepine taper, not another stay in rehab.
For anyone who already takes a benzodiazepine every day, one warning stands above everything else. Never stop a benzodiazepine suddenly, and never let a taper turn into an abrupt stop. Sudden discontinuation can trigger seizures and can be life-threatening. However a taper is shaped, it should be gradual and medically supervised.
Do you have to go to detox or rehab to stop drinking?
Not necessarily. However, if you have had a withdrawal seizure or delirium tremens before, or you have serious medical problems, a hospital is the safest place to stop drinking.
For other people, it is possible for a doctor to supervise the process at home, by telemedicine, with a supportive family member in the house. Your doctor prescribes the medications, stays in close contact through the first days, and is the person you call when something does not feel right.
Dr. Leeds supervises alcohol withdrawal at home for patients in Florida, with a nurse on site around the clock.
Interestingly, real access to a doctor is the one thing that many detox and rehab programs are short on. You may get a brief physical from the medical director on the day of admission, and after that, you may not see a physician again. You will, however, be invited to share your innermost feelings with a circle of strangers.
Of course, Alcoholics Anonymous, or AA, has helped many people to stop drinking, and a meeting that is helping you is worth keeping. Yet, meetings and a facility are not the only door, and medical treatment is not a second-tier option.
Is there an alternative to stopping cold turkey?
Yes. It is known as the Sinclair Method, or TSM, and the more technical name for it is pharmacological extinction. Instead of stopping all at once, you take a naltrexone tablet about one hour before your first drink, every time you drink.
Naltrexone blocks opioid receptors in the brain. Alcohol releases endorphins, the brain’s own reward chemicals, and with those receptors blocked, the reward is thought to be muted. With time, the learned habit weakens and the amount comes down, as explained in this longer article on how the Sinclair Method works.
You do not have to stop drinking before you start, and success is measured by reduced drinking, not by abstinence. In fact, it works like a taper. The drinking comes down gradually, over months.
Does it work for everyone? No. The naltrexone label itself says that the drug was not uniformly helpful to all patients, and that the expected effect is a modest improvement.
Naltrexone is not addictive, and it does not produce a high. Still, it is not as harmless as an over-the-counter pill. Nausea and headache are among the most common side effects, and liver injury has been reported, most clearly at doses higher than recommended.
One warning matters more than the rest. Naltrexone must never be taken by anyone who uses opioid pain medication, or who is physically dependent on any opioid, because it triggers sudden and severe withdrawal. A person must be free of opioids for at least 7 to 10 days before the first dose, and longer after a long-acting opioid.
Why not wait until things get worse before asking for help?
An analogy that might help is a play date with a gorilla. Have you ever played games with a gorilla? Probably not. Imagine being sent into the gorilla’s habitat at the zoo for a game of tag, and deciding after a few minutes that you would like to go home. The play date is not over until the gorilla decides it is over.
While this is not a perfect analogy, active addiction to alcohol works much the same way. You do not get to say when it ends, and often, it takes a tragedy, or the people who love you, to end it for you.
In Florida, where Dr. Leeds practices, a law known as the Marchman Act allows a family to ask a judge to order a person into assessment and treatment. Yet, medical treatment that you choose early, with your own doctor, is better than treatment that a court chooses for you later.
The key is to ask for help before the gorilla decides.
If you have been drinking heavily for years, is it too late for your brain?
No. At least some of the changes in the brain, and the changes in thinking and mood that come with them, can improve and possibly reverse over months without drinking.
While some damage may be permanent, especially after decades of heavy drinking or after Korsakoff syndrome, the brain has ways of compensating. How much will come back? No doctor can say that in advance. Yet, people do make remarkable improvements in memory and thinking over the months and years after they stop.
Nutrition matters during this time, and your doctor will likely recommend thiamine. Beyond that, the evidence for supplements that promise to heal the brain is limited, so speak with your doctor about which ones, if any, make sense for you.
The damage stops adding up when the drinking stops, and less drinking means less damage. You only get one brain, and the best time to start protecting it is now.
In Dr. Leeds’ practice, alcohol use disorder and gray area drinking are treated with naltrexone and the Sinclair Method by telemedicine throughout Florida. The practice also supervises alcohol withdrawal at home, with a nurse on site 24 hours a day. Patients work directly with Dr. Leeds, do not have to stop drinking before the first visit, and are never required to attend group meetings. To ask about an appointment, use the contact form.
This article is educational. It is not medical advice, and reading it does not create a doctor-patient relationship. Decisions about starting, continuing, or tapering any medication should be made with your own physician.
