Central nervous system stimulants are used to treat several health conditions, such as attention deficit hyperactivity disorder (ADHD) and narcolepsy. They also have other uses. These medications work by increasing the levels of certain chemicals in your brain that help improve focus, attention, and energy levels. They come in different forms, including oral pills and extended-release capsules. Examples include amphetamine salt combo (Adderall, Adderall XR), lisdexamfetamine (Vyvanse), and methylphenidate ER (Concerta).