Ritalin

Ritalin, the trade name for methylphenidate, is a central nervous system stimulant. It is a medication prescribed to treat attention-deficit/hyperactivity disorder (ADHD) as well as narcolepsy.  Ritalin has a notably calming effect on hyperactive children and a "focusing" effect on those with ADHD so that, when taken as prescribed, it can be a valuable medicine.  

Because of its stimulant properties, however, there have been reports of its abuse. In college, some students take the drug for recreational purposes or to help them study. Youth have reportedly sold their own prescriptions at school. Parents have been admitted to treatment for abusing their children’s prescriptions. According to reports by youth treatment providers, some adolescents continue to abuse the drug, which is most easily available through diverted prescriptions. Some stimulant users mix Ritalin (or "West Coast") with heroin, or with both cocaine and heroin for a more potent effect.

Because stimulant medicines such as Ritalin do have potential for abuse, the U.S. Drug Enforcement Administration (DEA) has placed stringent controls on their manufacture, distribution, and prescription.