Amphetamine is a potent central nervous system (CNS) stimulant of the phenethylamine class that is approved for the treatment of attention deficit hyperactivity disorder (ADHD) and narcolepsy .  Amphetamine was discovered in 1887 and exists as two enantiomers : levoamphetamine and dextroamphetamine . [note 1]  Amphetamine refers to equal parts of the enantiomers, ., 50% levoamphetamine and 50% dextroamphetamine.   Amphetamine is also used as a performance and cognitive enhancer , and recreationally as an aphrodisiac and euphoriant .     Although it is a prescription medication in many countries, unauthorized possession and distribution of amphetamine is often tightly controlled due to the significant health risks associated with uncontrolled or heavy use.   As a consequence, amphetamine is illegally synthesized by clandestine chemists , trafficked, and sold.  Based upon drug and drug precursor seizures worldwide, illicit amphetamine production and trafficking is much less prevalent than that of methamphetamine .