When people think of substance abuse, they automatically think of alcohol and illegal drugs or street dugs, such as cocaine and heroin. What most people are not going to think about are the drugs that are given to people with the permission of their doctor. When people abuse a substance, it is not always something that is illegal. It can be prescription drugs that people, even teenagers, sometimes abuse. In fact, studies show that while pain medication is one of the most abused substances in North America, medications such as cough syrup are often abused by young adults.