Non-medical use of prescription stimulants can lead to irregular heart rate, hypertension, cardiovascular system failure, stroke and seizures, while non-medical use of prescription opioids can cause respiratory suppression and overdose. Most of drug-realted deaths worldwide are due to either prescription opioid or heroin overdoses. Misuse of prescription drugs is highest among young adults ages 18-25. After marijuana and alcohol, prescription drugs are the most commonly misused substances by Americans age 14 and older. Teens misuse prescription drugs for a number of reasons, such as to get high, to stop pain, or because they think it will help them with school work. Many teens get prescription drugs they misuse from friends and relatives, sometimes without the person knowing.

The three classes of medication most commonly misused are as follows:

• Opioids - usually prescriped to treat pain
• Central Nervous System (CNS) Depressants (including tranquilizers, sedatives, hypnotics) - used to trewat anxiety and sleep disorders
• Stimulants - most often prescribed to treat attention-deficit hyperactivity disorder (ADHD)