An addiction is the repeated use of a drug. An addict (person with an addiction) uses the drug again and again. Addicts will continue to use the drug, even if the drug hurts them. Addiction causes cravings for the drug. A craving is an intense need for the drug's effects. Drug tolerance occurs when a person's body adapts to a drug. The body becomes more resistant to the drug and craves the drug all the time. If a dependent person stops taking the drug, they may become very sick or die. Medical help is often required to negate (help) addiction. Addiction and dependence can happen separately from each other. People can be addicted to things that are not drugs (like gambling or sex). 