Ritalin is a brand name of the drug Methylphenidate (MPH), a stimulant best-known for its use to treat attention-deficit hyperactivity disorder (ADHD), but also used for other symptoms, including cancer-related fatigue. MPH stimulates the central nervous system of the brain reducing impulsive behavior, and improving concentration. Known side-effects include difficulty in sleeping and mood swings. There is evidence that MPH produces small reductions in height and weight. Studies continue into potential carcinogenic risks and chromosomal abnormalities associated with prolonged use.