Alcoholism (Alcohol Abuse or Dependence)

Because many drinkers occasionally imbibe to excess, temporary alcohol-related pathology is common in nonalcoholics, especially those in the late teens to the late twenties. When repeated problems in multiple life areas develop, the person is likely to meet criteria for alcohol abuse or dependence.

Definitions and Epidemiology

Alcohol dependence is defined in the Fourth Diagnostic and Statistical Manual (DSM-IV) of the American Psychiatric Association as repeated alcohol-related difficulties in at least three of seven areas of functioning that cluster together over any 12-month period. A special emphasis is placed on tolerance and/or withdrawal, a condition referred to as "dependence with a physiological component," which is associated with a more severe clinical course. Dependence occurs in both men and women and in individuals from all socioeconomic strata and of all racial backgrounds. The diagnosis predicts a course of recurrent problems with the use of alcohol and the consequent shortening of the life span by a decade or more. In the absence of alcohol dependence, an individual can be given a diagnosis of alcohol abuse if he or she demonstrates repetitive problems with alcohol in any one of four life areas that include social, interpersonal, legal, and occupational problems, or repeated use in hazardous situations such as driving.

The lifetime risk for alcohol dependence in most western countries is about 10 to 15% for men and 5 to 8% for women. When alcohol abuse is also considered, the rates are even higher. The typical alcoholic is a blue- or white-collar worker or homemaker and not the stereotypical homeless individual.

Genetics of Alcoholism

Alcoholism is a complex genetically influenced disorder; genes explain about 60% of the risk. The importance of genetic influences is supported by a higher risk in the identical versus fraternal twin of an alcoholic and a fourfold increased risk in children of alcoholics even if adopted at birth and raised without knowledge of their biologic parents.

A variety of independent genetically influenced characteristics likely combine to explain the contribution of hereditary factors. For alcoholism and other substance dependencies, some families appear to carry an enhanced risk through high levels of impulsivity, as can be seen in the antisocial personality disorder. In other families the risk is associated with vulnerability for several independent psychiatric disorders such as schizophrenia and manic-depressive disease. A diminished alcoholism risk is seen in approximately half of Asian men and women; this is due to an inactive form of the enzyme ALDH, which results in higher levels of acetaldehyde following alcohol ingestion. A significant proportion of the vulnerability for alcoholism appears to relate to genes that affect the intensity of the response to alcohol. Most studies have shown that 40% of some subgroups at high risk for future alcoholism (e.g., offspring of alcoholics) require higher blood alcohol concentrations to produce the effects seen at lower blood levels in most other people. This relatively low response to alcohol predicts the risk for alcohol-related problems over the next decade, including alcohol use disorders.