When does someone cross that boundary between recreational alcohol use and dependence? Three main symptom clusters have been used to help draw this distinction:

Loss of Control. Some people have defined addiction by focusing on the degree of control over alcohol. In the past, addiction experts called this psychological dependence. Loss of control also becomes evident when a person makes repeated, but unsuccessful, attempts to cut down or stop drug use. Finally, loss of control is marked by compulsive thoughts and actions. Much of the day is spent either thinking about getting high again or recovering from a previous high.

Maladaptive Consequence. A second measure of alcohol dependence is the presence of negative psychological, social, and medical consequences. Alcohol dependence is the leading cause of missed days at work. Alcohol dependence is also associated with severe medical problems. People who continue to use alcohol despite adverse effects on their health, occupational or social functioning show symptoms of alcohol dependence.

Biological Adaptation. Some substance abuse experts define dependence solely with physiological adaptation to alcohol. In the past this has been referred to as physical dependence. Physical dependence is shown by either tolerance or withdrawal. Tolerance is defined as a decrease in the response to alcohol as use continues over time. Thus, it takes a progressively larger amounts of alcohol to produce the same effect. Chronic alcohol users may also experience withdrawal symptoms such as rapid heart rates or excessive sweating when they stop or decrease alcohol drinking. People who show either physical tolerance or symptoms of withdrawal are said to be physically adapted to the drug.