Alcohol dependence is a chronic but often progressive disease that includes problems in controlling one's drinking, being preoccupied with alcohol, continuing to use alcohol even when it causes problems, having to drink more to get the same effect (physical dependence), or having withdrawal symptoms when one rapidly decreases or stops drinking. Twin, family, and adoption studies have indicated that the susceptibility to alcohol dependence is genetically influenced, with a heritability of 50–60% (1–3). At least part of the cause of alcohol dependence is attributable to gene variation.
