I am unclear if you are asking about youth who use prescribed medication and take it as it is regulated or if you are asking about youth who are using what they find to self medicate.
This article on “Good Drugs Gone Bad” might interest you.
When people speak of drug abuse, one immediately thinks of drugs such as marijuana and cocaine. However, people rarely think of the common drugs found in their homes and medicine cabinets. These pharmaceuticals typically are used for medicinal or “good” purposes; however we are starting to see an alarming trend of abuse of this medicine. According to the Drug Enforcement Administration, nearly 7 million Americans abuse prescription drugs. That’s more than the total number abusing cocaine, heroin, ecstasy and other drugs – and the number has increased 80% in the past 6 years.