Amphetamine is a stimulant that at higher doses results in an increase in energy and activity, hyper-responsiveness to environmental stimuli, euphoria, and a number of physiological signs of hyperactivation. At lower doses, it improves attention, wakefulness, mood and reduces appetite. It was first synthesized in 1887 by a Romanian chemist named Lazăr Edeleanu, although no use for it was known until 1927 that pharmacologist Gordon Alles, seeking a decongestant alternative to ephedrine, tested the chemical on himself. Amphetamine in various forms is medically approved to relieve symptoms of Attention Deficit/Hyperactivity Disorder (ADHD), Narcolepsy, and produce weight loss. Amphetamine is sometimes used off-label to treat conditions such as Depression and Chronic Fatigue Syndrome.
Amphetamine exists in two stereoisomers, dextroamphetamine and levoamphetamine; amphetamine refers to the racemate—equal amounts of dextro- and levoisomers. Dextroamphetamine has more potent central stimulant effects than levoamphetamine, which has more prominent peripheral stimulant effects. This is partly due to dextroamphetamine having greater overall effect on dopamine. However, levoamphetamine increases dopamine in the prefrontal cortex, where dopamine reuptake depends on the norepinephrine transporter. Amphetamine medications include (racemic) amphetamine, dextroamphetamine, and mixtures like Adderall containing approximately 75% dextro- and 25% levoamphetamine. Dextroamphetamine is also available as lisdexamfetamine, an abuse resistant prodrug that slowly converts to dextroamphetamine and l-lysine in the blood stream. Amphetamine medications are most often salts in either immediate release or time release forms. In addition to lisdexamphetamine, new formulations include amphetamine base in a liquid suspension. Despite controversy, stimulants such as amphetamines remain the first line treatment for ADHD, superior to behavioral methods and shown to reduce risks of recreational drug use.
Amphetamine's pharmacological mechanism of action is increasing the synaptic levels of biogenic amine neurotransmitters such as norepinephrine, dopamine, and to a lesser degree serotonin. Without a prescription, amphetamine is illegal in most countries, and when sold illegally for recreational use amphetamine and methamphetamine are commonly known as "Speed". In the United States, non-medical amphetamine is generally diverted from prescribed amphetamines, whereas methamphetamine is typically produced illicitly.
Abnormal Psychology, Rosenhan & Seligman, 1984