Ritalin, also known as methylphenidate, is a central nervous system stimulant prescribed primarily to treat attention deficit hyperactivity disorder (ADHD) and narcolepsy. It works by increasing the levels of dopamine and norepinephrine in the brain, which helps improve focus, attention, and impulse control. Ritalin is available in immediate-release and extended-release formulations. It is often used as part of a comprehensive treatment plan that may include behavioral therapy. Common side effects may include insomnia, decreased appetite, and increased heart rate. While generally safe and effective, Ritalin carries risks of misuse, dependence, and potential for addiction, requiring careful medical supervision.