Alcohol is a drug that acts as a depressant and slows down the brain and nervous system. It is the most widely used drug in Australia. ​The effects of alcohol depends on how much you drink, how quickly you drink it, your size and weight, and whether you are male or female. It can also depend on how good your general health is, how healthy your liver is, where you drink, whether you drink alone, whether you use alcohol with other drugs including medications and if there is a family history of alcohol and other drug dependence.