http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001940/

Causes, incidence, and risk factors

There is no known cause of alcohol abuse or alcoholism. Research suggests that certain genes may increase the risk of alcoholism, but which genes and how they work are not known.
How much you drink can influence your chances of becoming dependent. Those at risk for developing alcoholism include:

• Men who have 15 or more drinks a week
• Women who have 12 or more drinks a week
• Anyone who has five or more drinks per occasion at least once a week

One drink is defined as a 12-ounce bottle of beer, a 5-ounce glass of wine, or a 1 1/2-ounce shot of liquor.
You have an increased risk for alcohol abuse and dependence if you have a parent with alcoholism.
You may also be more likely to abuse alcohol or become dependent if you:

• Are a young adult under peer pressure
• Have depression, bipolar disorder, anxiety disorders, or schizophrenia
• Have easy access to alcohol
• Have low self-esteem
• Have problems with relationships
• Live a stressful lifestyle
• Live in a culture alcohol use is more common and accepted

Alcohol abuse is rising. Around 1 out of 6 people in the United States have a drinking problem.