Adderall is a prescription medication that contains a combination of amphetamine and dextroamphetamine, both of which are central nervous system stimulants. Adderall is available in both immediate-release (IR) and extended-release (XR) formulations. The IR version lasts around 4-6 hours, while the XR version provides effects for up to 12 hours. It is classified as a Schedule II controlled substance due to its high potential for abuse and dependence.