Written by: THE BALANCE
Medically reviewed by Dr. Sarah Boss, MD
Last updated: January 19, 2026
Fact checked
Quick Summary
  • Depending on the amount consumed and the frequency of consumption, these dangers and side effects also vary.
  • Heavy drinkers are at a risk of facing many issues within their organ systems.  In this article, we will begin by discussing the effects of alcohol on the human body and will further talk about its effect on the nervous system and the brain.
  • Since alcohol is a depressant, it directly affects the brain and can lead to many psychological and psychiatric issues.
Reading time: 11 min

Alcohol consumption is common. It can, however, lead to adverse side effects. Depending on the amount consumed and the frequency of consumption, these dangers and side effects also vary. Heavy drinkers are at a risk of facing many issues within their organ systems. In this article, we will begin by discussing the effects of alcohol on the human body and will further talk about its effect on the nervous system and the brain. Since alcohol is a depressant, it directly affects the brain and can lead to many psychological and psychiatric issues. We will also discuss how alcohol could affect the brain of an unborn child. 

Alcohol; a drug commonly consumed around the world for various reasons, including leisure and to forget one’s woes. It is also used as a celebratory drink and is considered a great companion when watching sports. However, it can have detrimental effects on the human body. 

Consumption of alcohol can lead to stomach ulcers. The alcohol irritates the stomach lining. This is why when people drink heavily, the alcohol build-up can induce vomiting. The stomach produces more juices, and so long-time drinkers do not feel hungry due to the presence of extra juices, and therefore they do not get enough nutrients for the body. 

Similarly, the small intestines and colon get irritated too. It disrupts the speed at which food passes through and causes diarrhea. This can also lead to heartburn. Alcohol tampers with hormones in the brain that control kidneys. Due to this, the kidneys produce too much urine.  This means you’ll have to go more frequently, which might dehydrate you. The increased effort and harmful consequences of alcohol can wear down your kidneys if you frequently drink for years. (source: NIAAA, n.d.)

Your liver breaks down almost all the alcohol you drink. In the process, it handles a lot of toxins. Over time, heavy drinking makes the organ fatty and lets thicker, fibrous tissue build up. That limits blood flow, so liver cells don’t get what they need to survive. As they die off, the liver gets scars and stops working as well; a disease called cirrhosis.

One night of binge drinking can jumble the electrical signals that keep your heart’s rhythm steady. If you do it for years, you can make those changes permanent. And alcohol can wear your heart out. Over time, it causes heart muscles to droop and stretch like an old rubber band. It can’t pump blood as well, and that impacts every part of your body.

Depression Effects on the Brain (source: NIAAA, n.d. (brain))

Alcohol widens your blood vessels, making more blood flow to your skin. That makes you blush and feel warm and toasty. But not for long. The heat from that extra blood passes right out of your body, causing your temperature to drop. On the other hand, long-term, heavy drinking boosts your blood pressure. It makes your body release stress hormones that narrow blood vessels, so your heart has to pump harder to push blood through.

Although you would not associate a cold with a night of drinking, there could be a relationship. Your immune system is slowed by alcohol. Your body is unable to produce the necessary amount of white blood cells to combat infections. As a result, you’re more likely to feel sick over the next 24 hours after drinking. Heavy drinkers who have been drinking for a long time are significantly more prone to acquire diseases like pneumonia and TB.

Other effects such as hormonal imbalance, hearing loss, thinning of bones and muscles can also result from drinking excessively. (source: MedlinePlus, n.d.)

As considered above, alcohol affects the whole body negatively; however, it is the brain that takes a toll. It hinders the brain’s communication pathways which can, in turn, lead to short-term and long-term effects. It can also affect the way your brain processes information. Alcohol intoxication may be divided into various stages:

Subliminal Intoxication: This is the initial stage of drunkenness, with a blood alcohol concentration (BAC) of 0.01–0.05. Even if you don’t appear to be inebriated, your response speed, demeanor, and judgment may be affected. After one drink, most men and women reach this level, depending on their weight.

Euphoria: Your brain produces more dopamine in the early stages of drinking. This substance is connected to pleasure. You may feel comfortable and confident when in bliss.  (source: CDC, n.d. (alcohol & health))

Excitement: The occipital lobe, temporal lobe, and frontal lobe in your brain are all affected by this level of intoxication. Too much alcohol can cause side effects specific to each lobe’s function, such as blurred vision, slurred speech and hearing, and a loss of control. The sensory information-processing parietal lobe is also affected. Fine motor skills may be lost, and your reaction time may be slowed. Mood swings, impaired judgment, and even nausea or vomiting are common during this stage.

Confusion: Disorientation is common with a BAC of 0.18 to 0.3. The cerebellum, which aids in coordination, has been harmed. As a result, you might require assistance walking or standing. At this point, blackouts, or temporary loss of consciousness or short-term memory, are likely to occur. This is due to a malfunction in the hippocampus, the part of the brain responsible for forming new memories. You could also have a higher pain threshold, which could put you at greater risk of injury.

Stupor: If your blood alcohol concentration (BAC) is 0.25, you may show signs of alcohol poisoning. All mental, physical, and sensory functions are severely impaired at this time. Passing out, suffocation, and injury are all possible and extremely likely outcomes. (source: WHO, n.d.)

Coma: You’re at risk of getting into a coma if your blood alcohol level is 0.35. This is caused by problems with breathing, circulation, motor reactions, and reflexes. This stage puts a person’s life in jeopardy.

Death: A blood alcohol concentration (BAC) of 0.45 or higher may result in mortality from alcohol poisoning or the inability of the brain to manage the body’s critical processes.

It is not a discovery that alcohol has a significant and tremendous impact on the brain. The human brain is intricately complex and highly sensitive to external stimuli. The brain works the way it does because of the innumerable chemical balances. Even a slight disturbance can alter this balance and hence affect the processes not only occurring in the brain but also throughout the body. And what alcohol does is messes up this fragile balance of chemicals and changes our actions, thoughts, and emotions. (source: SAMHSA, n.d.)

Alcohol affects the neurotransmitters in the brain, which act as messengers and transmit messages from one neuron to another. Psychologically, the effects of alcohol can initially start with only some confusion and disrupted muscle coordination, but it can eventually lead to larger, more alarming effects such as memory loss and depression. The user becomes uninhibited, confident, and “carefree.” They may also experience vision problems. He/she seems relaxed and feels that stress is relieved. However, this is short-lived, and soon the alcoholic starts becoming more and more stressed over unnecessary things, leading to anxiousness and depression. As expected, tolerance and dependence result in trying to try and alleviate the depression; not knowing it only makes the situation worse – it is possible that problems start occurring in the ever-developing brain. 

Depression and anxiety are two long-term effects of alcohol on the brain, and they can result in the person developing disorders such as clinical depression and GAD (generalized anxiety disorder). Dementia is another common side effect of alcohol on the brain. Blackouts and difficulty concentrating also are common in heavy drinkers, which in turn impedes intellect, as we will find out later. Alcohol does not kill brain cells, but it does affect them so much so that alcoholics start feeling “something taking over” them when they try and refrain from drinking. Knowing this is enough to make a person leave the bad habit. 

Alcohol greatly slows down the nervous system, which is why it is known as a “depressant.” Thus, drinking alcohol fairly regularly over a period of time can dim one’s intelligence and cognitive functioning. Even moderate drinking, even for someone who is not an alcoholic, can impact the intellect, according to researchers, and shrink the hippocampus. The previous assumption that moderate alcohol increases brain functioning has now been proven incorrect as no amount of alcohol improves the functioning of the brain – it only ruins it tremendously.  (source: NHS, n.d.)

Memory loss as a result of blackouts, or sometimes even without, interferes with learning and intellectual abilities. This, coupled with hazy concentration, means that the person finds it increasingly difficult to not only learn new information but also retain it. Issues with making judgments are also common, and the person may need help making the simplest decisions, such as which pair of jeans to buy or what to order with guests at a dinner. 

Discontinuation of drinking alcohol can rid the person of these horrendous side effects, albeit if they had indulged only in a handful of drinks. Of course, a hardcore alcoholic needs more than just willpower (for example, rehab) to let go of the addiction and free themselves of the psychological and intellectual side effects, and it is surely possible. In the short term, the person feels relaxed, as aforementioned, but this can later disrupt normal cognitive workings, in which remembering where you promised to meet a friend becomes hard. It is proven, in various studies, that people who have alcohol-related disorders have a lower IQ than the general population, whether they are in their young adulthood, middle life, or late adulthood. Their intelligence also decreases linearly with age. 

Women who are pregnant are advised against the use of alcohol for the primary reason that it directly impacts the health of the baby. If alcohol can harm the brain of a mother ingesting it, it can also impact the brain of the fetus during development, and its effects can be evident after birth. In fact, the most common cause of birth defects and disabilities in babies is due to alcohol consumption of the mother. (source: NIDA, n.d.)

Alcohol is easily liable to pass through the blood of the mother, through the placenta, into the fetus’ blood. When this happens (and it is probable in most cases), the baby’s cells are damaged, and growth is significantly affected. Particularly, the cells in the spinal cord and the brain – that is, the central nervous system, are damaged. The baby may be born abnormally small and may not grow as much as other children their age if the mother was a regular drinker of alcohol during pregnancy. Such disruptions to normal fetal growth caused by alcohol are termed Fetal Alcohol Spectrum Disorders (FASDs). FAS / FASD, or Fetal Alcohol Syndrome / Fetal Alcohol Syndrome Disorder, is the most severe subcategory of FASDs caused by drinking alcohol while pregnant. One of the major side effects is the baby having learning as well as behavioral problems. Their IQ is either low, or they have an intellectual disability. Furthermore, just like in adults who start having slurred speech, babies of alcoholic mothers also develop speech problems and are born with speech and/or language delays.

The fetal brain is affected in such a way that once the child is old enough to understand the concept of orders and distance, he/she finds it hard to follow directions. They also have difficulty controlling and managing their emotions and also have poor memory and problems in shifting focus. Even daily life skills of such children become impaired, and something as simple as counting money in a piggy bank, feeling hungry or full at the right time, or telling the time becomes a monumental cognitive task. 

People can live a life immune to such dreadful side effects if they steer away from alcohol abuse and not only save their own mental and physical health but also make sure their children are not born with any defects because of their own irresponsible behavior.

FAQs

How much alcohol is safe to drink per day? 
According to the US Dietary Guidelines, 2015-2020, people should limit their alcohol-related risks by drinking in moderation, meaning up to 1 serving of alcohol per day for women and up to 2 servings per day for men.
Can alcohol consumption affect the fetus? 
Your baby cannot process alcohol as well as you can, and too much exposure to alcohol can seriously affect their development. Drinking alcohol, especially in the first three months of pregnancy, increases the risk of miscarriage, premature birth, and your baby having a low birthweight.
Does alcohol lead to memory loss? 
Whether it’s over one night or several years, heavy alcohol use can lead to lapses in memory. This may include difficulty recalling recent events or even an entire night. It can also lead to permanent memory loss, described as dementia.

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