Alcohol as a depressant that affects the central nervous system, but initially and in small doses, it is also a stimulant.

Research has shown that approximately 86 per cent of adults in the United States have consumed alcohol at some time. In 2019, nearly 26 per cent of American adults also engaged in binge drinking.

A large 2018 study indicated that any level of drinking is harmful. Over 140,000 people in the US die from overconsuming alcohol each year. Alcohol overuse also increases the risk of developing other conditions, including depression.

In this article, we explore alcohol impact on the central nervous system (CNS) in more detail to highlight the differences between stimulants and depressants, and alcohol use disorder. It also answers some common questions about alcohol.

Alcohol is a psychotropic depressant that affects the CNS. A psychotropic substance impacts the brain and can affect thoughts, mood or behaviour. The type of alcohol in alcoholic beverages is ethanol, or ethyl alcohol. Manufacturers create alcoholic drinks through a process called fermentation. During this process, yeast converts carbohydrates into alcohol.

The percentage of alcohol varies depending on the type of beverage. A standard beer may contain about five per cent alcohol, whereas one portion of a distilled spirit could contain 40 per cent alcohol.

Alcohol functions as a depressant by slowing down brain activity. A person drinking alcohol may experience impaired judgment or slower reaction times. Drinking alcohol may also lead to dehydration.

When alcohol enters the body, most of it is absorbed into the bloodstream through the intestines. Blood, and therefore alcohol, is quickly distributed throughout the body and the brain. This happens faster than the liver can metabolize and eliminate alcohol.

In the brain, alcohol increases the neurotransmitter gamma-aminobutyric acid (GABA), which results in lower levels of anxiety, stress and fear. Neurotransmitters are the chemicals that control communication between nerve cells.

Excessive alcohol use can cause a number of health problems, including: liver disease, pancreatitis, elevated blood pressure, sudden infant death syndrome, aggressive behaviour, accidental injuries, alcohol use disorder, heart disease, stroke, hypertension, cognitive disorders, dementia and foetal alcohol syndrome.

Research has also shown that drinking alcohol increases the risk of developing cancer.

One of the most common types of stimulant drugs is amphetamines. Doctors may prescribe stimulants to individuals with attention deficit hyperactivity disorder (ADHD) or narcolepsy. Other stimulants include caffeine, cocaine and methamphetamine.

Individuals who overuse stimulants may experience: chest pain, vomiting, abdominal cramping, sweating, headaches or dizziness.

Under the guidance of a medical professional, stimulants may be helpful for certain individuals. However, misuse of stimulants can have serious health consequences, including physical dependence and stimulant addiction, also known as stimulant use disorder.

Depressants cause slower brain activity, leading to muscle relaxation and a calm mood. Some examples include benzodiazepines and barbiturates. Prescription depressants can help treat conditions such as: panic disorder, stress, anxiety, insomnia or seizures.

Although depressants can help treat certain conditions, misusing these substances can cause side effects that may include: impaired coordination, blurry vision, dizziness, speech problems, low blood pressure, nausea or vomiting or confusion.

If a person takes depressants for a long time, they may develop physical dependence and substance use disorder.

Individuals with alcohol use disorder (AUD) continue to consume alcohol despite experiencing negative consequences. Although AUD cases may differ in severity, people who receive effective treatment can fully recover. Certain people are more likely to develop AUD than others. This may include people: with a family history of AUD, who began drinking earlier in life, with mental health conditions such as depression, who have a history of trauma, who regularly binge drink or drink heavily.

People who are living with AUD may deal with a wide array of symptoms, including: drinking more or longer than planned, difficulty thinking about anything other than drinking, neglecting work or hobbies to drink, needing to drink more to achieve the same effect and getting into dangerous situations after drinking.

Long-term overuse of alcohol can cause physical and psychological dependence. People who are dependent on alcohol may experience withdrawal symptoms when they try to quit drinking. These symptoms may range from nausea and anxiety to seizures and hallucinations.

Heavy drinking can also lead to alcohol poisoning. Consuming too much alcohol too quickly can affect breathing, body temperature and heart rate. In extreme cases, alcohol poisoning can cause brain damage or even death.

There are many effective treatment options available for AUD. Certain medications may help. Naltrexone and acamprosate can both reduce heavy drinking and support abstinence. They may also reduce alcohol cravings for certain people.

Another medication, called disulfiram, causes negative symptoms such as nausea after consuming alcohol. These side effects may help discourage people with AUD from drinking.

Treatment for AUD can also include counselling. A therapist can help individuals with AUD develop coping skills to reduce stress and manage cravings. People may develop an addiction to alcohol after using it to cope with stress or traumatic life events. Addressing emotional or mental health concerns can help people with AUD find ways to cope that do not involve alcohol.

Alcohol acts on the brain and may increase feelings of relaxation. This may cause positive emotions in the short term. However, drinking too much can cause negative side effects, such as nausea and vomiting.

Consuming any form of alcohol carries certain health risks. The amount of alcohol a person consumes affects them more than the type of alcohol they drink. Research suggests that light or moderate wine consumption may reduce the risk of dementia, but drinking an excessive amount of wine increases the chance of dementia and cognitive decline.

• A Medical News Today report