Effects of Alcohol

Long-term, heavy alcohol use affects the whole body, leading to neurological damage, gastrointestinal problems, heart disease, reproductive disorders, cancer and death. Additionally, the psychological and social impacts of alcohol can be detrimental to a person’s well-being.

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Most people enjoy drinking alcohol because of its euphoric effects. Alcohol is rapidly absorbed in the body, and once it enters the blood stream, it quickly makes its way to the brain. How long alcohol stays in your system is dependent on a number of factors, from when you last ate to your gender and weight.

As the alcohol binds to the brain’s GABA receptors, it has a relaxing effect. Your inhibitions drop and you become more talkative and more self-confident. Alcohol also boosts the levels of the feel-good chemical serotonin in the brain, which contributes to the happy, buzzed feeling you get after having a drink or two.

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As alcohol affects different parts of the brain, other changes occur. Alcohol depresses the cerebral cortex, the wrinkled and folded outermost layer of the brain that controls language and thinking, clouding your judgment and thinking. You may have trouble seeing or hearing things, too, and become less sensitive to pain.

The limbic system, which regulates emotions, also goes haywire, resulting in exaggerated emotions. While one intoxicated person might dissolve into a puddle of tears, another might flitter around the bar telling everyone how much they love them. Others may become aggressive or combative.

Along with these extreme emotions, an intoxicated person may also have trouble remembering events. That’s because alcohol prevents the hippocampus, a structure inside the brain that controls learning and memory, from consolidating information and storing it as a memory. When this happens, you can experience alcohol-induced blackouts, a temporary form of amnesia that leaves you unable to recall conversations and activities that occurred during an episode of heavy drinking.

As the alcohol moves into the cerebellum, an area of the brain located near the top of the brain stem, your movement and balance are affected. You become less coordinated than when you’re sober, and you may even lose your balance and fall down. These classic signs of intoxication are the focus of field sobriety tests used to determine if a driver is under the influence.

When alcohol makes its way to the pituitary gland, a walnut-sized gland that sits at the base of the brain behind the bridge of the nose, it inhibits the secretion of an important chemical called antidiuretic hormone (ADH).

Normally, ADH regulates the amount of water the kidneys reabsorb as they filter toxins from the blood. But when alcohol decreases ADH, less water is reabsorbed, and you need to make frequent visits to the restroom. All that urinating can also leave you dehydrated, contributing to next-day hangover symptoms such as a headache and dry mouth.

Effects of Binge Drinking

Consuming large amounts of alcohol during a short period of time, or binge drinking, can lead to alcohol poisoning. According to the National Institute on Alcohol Abuse and Alcoholism, a person is binge drinking when their blood alcohol content (BAC) reaches 0.08 percent. For most adults that equates to drinking five alcoholic beverages within a two-hour period if you’re a man or four within a two-hour period if you’re a woman.

When your blood alcohol content climbs to very high levels, it can begin to affect parts of the brain stem. It slows your breathing and heart rate and drops your body temperature. At this point, you may become incredibly drowsy or even lose consciousness. Your gag reflex may cease, leaving you susceptible to choking on your own vomit.

Breathing may slow or stop all together, leading to coma or death.

While alcohol overdose from binge drinking is a medical emergency, it’s not the only danger associated with alcohol use. Long-term, heavy drinking can wreak havoc on almost every major organ in the body and result in a number of alcohol-related diseases and disorders.

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Brain and Nervous System

Alcohol abuse causes long-term changes in brain chemistry. When someone drinks heavily for a long time, the brain begins to counteract the slowing effects of alcohol by increasing the activity of excitatory neurotransmitters so it can function more normally.

With the brain in this amped-up state, a person requires increasingly larger amounts of alcohol to achieve the desired effects — a phenomenon known as tolerance — and they experience distressing alcohol withdrawal symptoms if they suddenly stop drinking.

These changes, along with cravings to drink, end up causing alcohol dependence or addiction.

Chronic drinking can cause other types of brain damage. Frequent and excessive alcohol consumption damages an area in the back of the brain called the cerebellum, resulting in poor coordination and balance, difficulty walking, a tremor and involuntary back-and-forth eye movements known as nystagmus. Some people also develop peripheral neuropathy, which is damage to the peripheral nervous system that can cause muscle weakness, numbness, tingling and burning pain in their extremities.

This sort of damage usually occurs after 10 years of chronic drinking and shows on an MRI as shrinkage in the cerebellum. It is believed to be caused by the toxic effects alcohol has on the brain plus nutritional deficiencies — particularly of the B vitamin thiamine — that are common in alcohol addiction.

Alcohol-related thiamine deficiency can also damage the lower parts of the brain known as the thalamus and hypothalamus, causing a life-threatening condition called Wernicke-Korsakoff syndrome. Wernicke-Korsakoff syndrome can cause loss of muscle coordination, visual changes and profound loss of memory, including the inability to form new memories.

Drinking large amounts of alcohol can also increase a person’s risk of stroke by contributing to high blood pressure, diabetes, obesity and other medical conditions that can cause a stroke. Chronic alcohol consumption has also been linked to the development of epilepsy in some people.


When alcohol is flowing through the blood, it acts as a vasodilator, causing the muscular walls of blood vessels to relax and widen. This causes a drop in blood pressure and an increase in blood flow to the skin and tissues, which results in the feelings of warmth and the rosy glow that many drinkers experience.

As blood pressure drops, the pulse rate quickens as the heart works harder to ensure that internal organs are still getting all the blood they need to function properly.

There’s been a lot of buzz in the past several years about the potential heart health benefits of moderate alcohol consumption. While more than 100 studies have linked moderate drinking (up to one drink per day for women and two for men) to a reduced risk of heart attack, sudden cardiac death, ischemic stroke and other cardiovascular causes of death, according to Harvard University, the same is not true for heavy drinking.

Chronic, heavy drinking can contribute to high blood pressure, heart disease, irregular heartbeats and heart failure. One way alcohol contributes to the development of heart disease is by raising the level of certain fats in the blood called triglycerides, which contributes to coronary artery disease.

Digestive System

Alcoholic beverages also affect the gastrointestinal system. At the upper end of the GI tract, alcohol can cause heartburn and damage the mucosal lining of the esophagus, which can lead to a precancerous condition known as Barrett’s esophagus as well as esophageal cancer.

Excessive alcohol consumption can cause inflammation of the stomach lining called gastritis, which can cause a gnawing or burning pain in the upper abdomen as well as nausea and vomiting.

Alcohol also alters the muscular contractions of the small and large intestine, causing diarrhea and even intestinal bleeding. Alcohol decreases the absorption of a variety of nutrients in the small intestines, which can lead to nutritional deficiencies.

Excessive drinking is hard on other digestive organs, including the liver and pancreas. Combining alcohol with other substances can increase the likelihood of organ problems. For example, mixing Mucinex and alcohol can lead to liver damage.

Alcohol is metabolized by the liver and can cause fatty liver disease, which causes an accumulation of fat inside liver cells that makes it hard for the liver to function properly. This condition can develop rapidly in anyone who drinks alcohol, but is usually reversible if you stop drinking.

Thirty-five percent of heavy drinkers develop alcoholic hepatitis, which is an inflammation and destruction of liver cells and can lead to cirrhosis of the liver. In cirrhosis of the liver, the organ’s tissue becomes fibrotic and is eventually replaced by scar tissue. This severe form of liver damage can be life threatening and develops in 10 to 20 percent of heavy drinkers.

Long-term heavy drinking can also cause pancreatitis, a life-threatening condition in which the pancreas becomes inflamed and digestive enzymes begin to attack and destroy the pancreas. Symptoms of pancreatitis include upper abdominal pain that may radiate to the back, abdominal pain that worsens after eating, nausea, vomiting, fever and an elevated heart rate.

Pancreatitis is a medical emergency and usually requires hospitalization. Chronic pancreatitis can lead to the development of type 2 diabetes by damaging the pancreatic cells that produce insulin.

Immune System

Alcohol dampens the immune system, which lowers your body’s ability to fight off infections. It does this by reducing the number of white blood cells circulating in your blood that tackle harmful microorganisms, like bacteria and viruses. Alcohol also inhibits the body’s production of cytokines, which coordinate the body’s immune response.

This lowered immune response is why alcoholics are more susceptible to infections such as tuberculosis, pneumonia and septicemia and have increased cancer rates.

Psychological Effects

People often drink to try to make themselves feel better, but alcohol can have the opposite effect.

While the first drink or two you consume might make you feel more relaxed or happy, as you become more intoxicated, these euphoric sensations often give way to darker moods and emotions, such as sadness, anger, aggression and irritability.

Chronic alcohol use alters brain chemistry and can result in mental illness. Repeated, heavy use of alcohol causes anxiety. People with anxiety often deal with feelings of worry, nervousness and unease about upcoming events or situations.

In addition, alcohol and depression are closely associated. According to the Anxiety and Depression Association of America, about 20 percent of Americans with an anxiety or mood disorder, such as depression, are addicted to alcohol or another drug.

Alcohol abuse can also trigger signs and symptoms of psychosis and antisocial behavior, which can manifest both when someone is intoxicated and when someone is withdrawing from alcohol. Such symptoms usually disappear, however, after several weeks of sobriety.

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Sexual and Reproductive Health

While drinking can lower one’s inhibitions and may increase their sexual desire, excessive alcohol use has a number of adverse impacts on sexual health. Published in the Indian Journal of Psychiatry, one study of 100 alcohol-dependent men in India found that 72 percent suffered from some sort of sexual dysfunction, including premature ejaculation, low sexual desire and erectile dysfunction.

Anyone who’s familiar with the “beer goggle” effect — the idea that being intoxicated makes you see others as being more attractive than you normally would — will also understand how alcohol use can make a person more inclined to engage in risky sexual behaviors, which can lead to unintended pregnancy and acquiring sexually transmitted diseases, including HIV and hepatitis.

Alcohol has also been shown to reduce fertility and is a contributing factor in miscarriage, stillbirth and numerous birth defects, including fetal alcohol syndrome. Women who drink while pregnant have a higher risk of giving birth prematurely and having a low birth-weight baby.

In 2012, alcohol was attributed as the cause of 5.5 percent of all new cancer cases and about 5.8 percent of cancer deaths worldwide. Here in the United States, approximately 3.5 percent of all cancer deaths are related to alcohol consumption.

Alcohol has been linked to the development of head and neck cancer, esophageal cancer, liver cancer, colorectal cancer and breast cancer in women. It’s not just heavy drinking that can cause problems. A study published in the Journal of Clinical Oncology in November 2017 found that even light drinking can raise a woman’s risk of breast cancer and elevate the risk of a common type of esophageal cancer.

People who both smoke and drink, meanwhile, greatly increase their risk of developing certain types of cancer, such as mouth, throat and esophageal cancer, according to the National Cancer Institute.

Injuries and Violence

Heavy alcohol use is associated with an increased risk of violence and injuries, such as homicide, suicide, sexual assault, motor vehicle crashes, falls, drownings and burns. About 45 percent of the 1.8 million alcohol-related deaths that occur worldwide every year, according to the World Health Organization, are caused by injuries.

Social Impacts

It’s not just your body that alcohol is harming. Excessive alcohol consumption can also lead to a number of social problems, including lost work productivity, unemployment and family problems.

Alcoholics are more likely to end up divorced than non-alcoholics. Children of alcoholics, meanwhile, can suffer many ill effects from growing up in an alcoholic household and develop problems that often follow them well into adulthood.

Medical Disclaimer: DrugRehab.com aims to improve the quality of life for people struggling with a substance use or mental health disorder with fact-based content about the nature of behavioral health conditions, treatment options and their related outcomes. We publish material that is researched, cited, edited and reviewed by licensed medical professionals. The information we provide is not intended to be a substitute for professional medical advice, diagnosis or treatment. It should not be used in place of the advice of your physician or other qualified healthcare provider.

Amy Keller, RN, BSN
Content Writer, DrugRehab.com
As a former journalist and a registered nurse, Amy draws on her clinical experience, compassion and storytelling skills to provide insight into the disease of addiction and treatment options. Amy has completed the American Psychiatric Nurses Association’s course on Effective Treatments for Opioid Use Disorder and continuing education on Screening, Brief Intervention and Referral to Treatment (SBIRT). Amy is an advocate for patient- and family-centered care. She previously participated in Moffitt Cancer Center’s patient and family advisory program and was a speaker at the Institute of Patient-and Family-Centered Care’s 2015 national conference.
Medical Reviewer
Ashraf Ali
Psychiatrist, Los Angeles County Department of Mental Health

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