Substance Index

Stimulants (also known as "uppers") are a class of psychoactive substances that speed up the central nervous system. They increase energy, alertness, wakefulness, and focus. They also reduce appetite and fatigue. Stimulants mainly raise the levels of dopamine and noradrenaline, the drive and alertness chemicals of the brain. These raised levels are also the reason that a crash often follows the effects. The name comes from the Latin stimulare, which means "to goad on."