The primary, legitmate medical use of methylphenidate (Ritalin) is to treat attention deficit disorders in children. As with other Schedule II stimulants, the abuse of methylphenidate may produce the same effects as the abuse of cocaine or the amphetamines. It has been reported that the psychosis of chronic methylphenidate intoxication is identical to the paranoid psychosis of amphetamine intoxication.

Unlike other stimulants, however, methylphenidate has not been clandestinely produced, although abuse of this substance has been well documented among narcotic addicts who dissolve the tablets in water and inject the mixture. Complications arising from this practice are common due to the insoluble fillers used in the tablets. When injected, these materials block small blood vessels, causing serious damage to the lungs and retina of the eye.