Alcohol

Short-term effects of alcohol use include:

• Distorted vision, hearing, and coordination
• altered perceptions and emotions
• impaired judgment
• bad breath; hangovers

Alcohol abuse is a pattern of problem drinking that results in health consequences, social, problems, or both. However, alcohol dependence, or alcoholism, refers to a disease that is characterized by abnormal alcohol-seeking behavior that leads to impaired control over drinking.
Source: http://www.health.org/govpubs/rpo884/#alcohol

Some problems, like those mentioned above, can occur after drinking over a relatively short period of time. But other problems--such as liver disease, heart disease, certain forms of cancer, and pancreatitis--often develop more gradually and may become evident only after long-term heavy drinking. Women may develop alcohol-related health problems after consuming less alcohol than men do over a shorter period of time. Because alcohol affects many organs in the body, long-term heavy drinking puts you at risk for developing serious health problems, some of which are described below.

Alcohol-related liver disease. More than 2 million Americans suffer from alcohol-related liver disease. Some drinkers develop alcoholic hepatitis, or inflammation of the liver, as a result of long-term heavy drinking. Its symptoms include fever, jaundice (abnormal yellowing of the skin, eyeballs, and urine), and abdominal pain. Alcoholic hepatitis can cause death if drinking continues. If drinking stops, this condition often is reversible. About 10 to 20 percent of heavy drinkers develop alcoholic cirrhosis, or scarring of the liver. Alcoholic cirrhosis can cause death if drinking continues. Although cirrhosis is not reversible, if drinking stops, one's chances of survival improve considerably. Those with cirrhosis often feel better, and the functioning of their liver may improve, if they stop drinking. Although liver transplantation may be needed as a last resort, many people with cirrhosis who abstain from alcohol may never need liver transplantation. In addition, treatment for the complications of cirrhosis is available.

Heart disease. Moderate drinking can have beneficial effects on the heart, especially among those at greatest risk for heart attacks, such as men over the age of 45 and women after menopause. But long-term heavy drinking increases the risk for high blood pressure, heart disease, and some kinds of stroke.

Cancer. Long-term heavy drinking increases the risk of developing certain forms of cancer, especially cancer of the esophagus, mouth, throat, and voice box. Women are at slightly increased risk of developing breast cancer if they drink two or more drinks per day. Drinking may also increase the risk for developing cancer of the colon and rectum.

Pancreatitis. The pancreas helps to regulate the body's blood sugar levels by producing insulin. The pancreas also has a role in digesting the food we eat. Long-term heavy drinking can lead to pancreatitis, or inflammation of the pancreas. This condition is associated with severe abdominal pain and weight loss and can be fatal.
Source: http://www.niaaa.nih.gov/publications/harm-al.htm