Health A-Z

Medical Content Created by the Faculty of the
Harvard Medical School

Alcohol Dependence (Alcoholism)

What Is It?

Alcoholism (alcohol dependence) is the most severe type of drinking problem. There is no absolute number of drinks per day or quantity of alcohol that defines alcoholism. Rather, it is defined by how a person's body reacts to alcohol and how the person behaves and thinks when he or she drinks.

People with alcohol dependence:

• Develop tolerance — They need to drink more and more alcohol to feel the same effects. They can also drink more than other people without getting drunk.

• Develop withdrawal symptoms — If they stop or cut back on drinking, they can experience anxiety, sweating, trembling, trouble sleeping, nausea or vomiting, and, in severe cases, physical seizures and hallucinations.

• Want to stop drinking, but they can't.

• Lose control over the amount of alcohol they drink.

• Become preoccupied with drinking.

• Payless attention to other life activities.

• Ignore problems.

A person with alcohol dependence has come to rely on alcohol physically, psychologically and emotionally. The brain adapts to the presence of alcohol and undergoes persistent changes. When alcohol use suddenly stops, the body's accustomed internal environment changes drastically, causing symptoms of withdrawal.

Alcoholism can be linked to a long list of psychological, interpersonal, social, economic and medical problems. Alcoholism can increase the risk of depression and suicide and play a role in violent crimes, including homicide and domestic violence (abuse of a spouse or child). It can lead to traffic accidents and even accidents involving intoxicated pedestrians who decide to walk home after drinking. Alcoholism also can lead to unsafe sexual behavior, resulting in accidental pregnancy or sexually transmitted diseases.

Alcohol dependence increases the risk of liver disease (hepatitis and cirrhosis), heart disease, stomach ulcers, brain damage, stroke and other health problems. In pregnant women who drink alcohol, there is also the danger that the child will develop fetal alcohol syndrome, a cluster of health problems including unusually low birth weight, facial abnormalities, heart defects and learning difficulties.

The lifetime chance of developing alcoholism is very difficult to determine, but it is very common. In the United States, about 1 in 16 adults have severe problems with drinking and millions more are engaged in what experts consider risky drinking.

Alcohol problems are both biologically and environmentally based. People with a family history of alcohol dependence are at greater risk for developing the illness themselves. For example, if a parent has alcohol dependence, a child has a four-times greater risk of becoming alcohol-dependent. This is partly due to inheriting genes that increase vulnerability, perhaps by changing a person's physical responses to alcohol.

Environmental influences are important, too. Alcohol may be a big part of a person's social group. A person may turn to alcohol to get relief from stress (which frequently backfires, because the drinking causes problems of its own). Sometimes alcohol is used to blot out feelings of depression or anxiety. Family support and healthy friendships can reduce the risk.