Cathinones are a class of monoamine-releasing and reuptake-inhibiting stimulants defined by the presence of a beta-keto group on the phenethylamine backbone — structurally, they are the beta-keto analogs of amphetamines. The class spans from naturally occurring alkaloids in the khat plant (Catha edulis) to a vast array of synthetic derivatives that were a dominant force in the novel psychoactive substances market of the 2000s and 2010s, collectively known as "bath salts" in media coverage and "cathinones" or "synthetic cathinones" in pharmacological literature.
Natural cathinone — (−)-cathinone — is the primary psychoactive alkaloid in khat leaves, producing stimulant effects when fresh leaves are chewed. Khat has been used for millennia in East Africa (particularly Ethiopia, Djibouti, and Somalia) and the Arabian Peninsula (particularly Yemen) as a social stimulant comparable in cultural role to coffee or betel nut. Natural cathinone is about half as potent as amphetamine and rapidly oxidized to norephedrine as leaves wilt, explaining the cultural practice of chewing only fresh khat.
Synthetic cathinones emerged as a major class of research chemicals beginning around 2007, with mephedrone (4-methylmethcathinone, 4-MMC) becoming one of the most widely used recreational drugs in the UK by 2009–2010 before scheduling. Subsequent synthetic cathinones ranged from MDMA-like entactogens (methylone, MDPV) to powerful and highly addictive dopaminergic compounds (alpha-PVP, MDPV) associated with severe psychological adverse effects. The synthetic cathinone market has continued to expand despite progressive scheduling, with new structural modifications producing novel compounds that temporarily evade legal restrictions.