Ritalin or Methylphenidate Hydrochloride is a central nervous system stimulant used as an adjunct to other behavioral therapy to treat children with an Attention Deficit Hyperactivity Disorder (ADHD). It is not completely understood how the drug works, but presumably it activates the brain stem arousal system and cortex to produce its stimulant effect.

Some side effects might include increased hyperactivity, seizures, withdrawal depression and suicidal tendencies.