Alcoholism is a chronic disease in which the body becomes dependent on alcohol; because of this, alcoholism is also known as alcohol dependence. The disease is characterized by four main features: an overwhelming urge to drink (craving), an inability to stop once you have started drinking, withdrawal symptoms when you are not drinking, and the need for increasing amounts of alcohol to feel drunk (tolerance).

It also is possible to have problems with alcohol that are not as severe as alcoholism. If you engage in excessive drinking that negatively impacts your health or your personal and professional life but you are not physically dependent on alcohol, this is known as alcohol abuse.

The National Institute on Alcohol Abuse and Alcoholism (NIAAA) estimates that nearly eight million people — about four percent of American adults — are alcoholics, while another ten million are alcohol abusers. The actual number may be much higher but it can be difficult to identify everyone who has an alcohol problem since many of them do not seek treatment and may deny having a problem altogether.