Alcohol dependence is a chronic pattern of alcohol abuse. An alcoholic gets used to the effects of alcohol and requires more alcohol to get the desired effect. This is called tolerance. A person with alcohol dependence may experience an uncontrollable need for alcohol.
Alcohol is a depressant. At a blood alcohol level of 0.05%, thought, judgment and restraint are affected. At a level of 0.1%, motor skills become clumsy. When the blood alcohol level reaches 0.2%, the entire area of the brain that controls motor function is negatively affected. Alcohol also affects the parts of the brain that control emotions and behavior. At 0.3%, the person is likely to be confused and stuporous. An individual at a blood alcohol level of 0.4% or higher may go into a coma. If blood alcohol levels exceed 0.5%, an individual might choke on vomit or stop breathing.
Prolonged alcohol use can actually alter the genes in the brain. People with alcoholism may have impaired memory, poor concentration, and inability to focus after a distraction.
No one knows for sure what causes alcohol abuse and dependence. Factors that increase a person's chance of becoming dependent on alcohol include: