Answer:
Stimulants are a class of drugs that “stimulate” the body's central nervous system, which includes the brain and spinal cord. They increase the levels of catecholamines—a family of brain chemicals that includes dopamine. These chemicals are used in the brain processes to signal reward and motivation.
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.