Amphetamines are synthetic, mood-altering stimulant drugs that may be prescribed legally as a prescription drug to treat ADHD and narcolepsy or used illegally as a stimulant. Prescription amphetamines are sold under brand names Adderall or Ritalin. Illegally obtained amphetamines may be abused by snorting crushed pills or dabbing it onto gums. Amphetamines may also be referred to as speed or uppers.