Liver cirrhosis, high blood pressure, strokes and certain types of cancer are much more common among people who drink heavily over a long period of time. So are stomach upsets, poor concentration and difficulty sleeping. In a study conducted by the Addiction Research Foundation and the Department of Family Medicine at the University of Western Ontario, it was learned that excessive alcohol drinkers had more health and social difficulties as a result of their drinking than was expected in the average person. Those who feel they cannot get through the day without drinking, using illegal drugs or taking prescription drugs differently than recommended to lift their spirits, are likely addicted. Over time, someone who is addicted will often need to take larger amounts or the same amount more often in order to obtain the same effect.
Few people do it with the intention of doing harm.
Some people try it out of curiosity or because they want to fit in with a particular crowd. A few drinks sharpened my sense of humour. But my boss didn't think it was very funny when my hangovers made me late for work. Family history of addiction puts a person at higher risk. A variety of biological, social and personal factors also come into play.