central nervous system stimulant (SEN-trul NER-vus SIS-tum STIM-yoo-lunt)
A type of drug that increases the levels of certain chemicals in the brain and increases alertness, attention, energy, and physical activity. Central nervous system stimulants also raise blood pressure and increase heart rate and breathing rate. They are used to treat depression, attention deficit hyperactivity disorder (a disorder in which a person has problems paying attention, controlling actions, and remaining still or quiet), and narcolepsy (a sleep disorder). Also called CNS stimulant.