Abstract
The term "betel" most accurately refers to the betel pepper (Piper betle). Confusingly, this term is also frequently used to refer to a street drug that often-but not always-includes the betel leaf as a constituent. This linguistic misdirection only intensifies with terms such as "betel nut," which, in common usage, may refer to this same composite street drug or to a single isolated constituent of that street drug: the nut of the areca palm (Areca catechu), which is otherwise wholly unrelated to the betel pepper. This composite street drug, colloquially referred to as "betel" or "betel nut" or "betel quid," is one of the most frequently used psychoactive substances in the world. It carries a cultural legacy spanning over 10,000 years and a current user base numbering in the hundreds of millions. Its primary psychoactive constituent is arecoline, a well-established parasympathomimetic agent. Early studies exploring arecoline's ability to modulate cholinergic signaling pathways and exert therapeutic psychiatric effects on conditions such as Alzheimer's disease were initially mired by intolerable parasympathetic side effects. Indeed, over the course of its long history, various hints regarding the therapeutic utility of arecoline have been obfuscated by a variety of challenges which have only recently been overcome. Now, developments in psychopharmacology and our growing understanding of neurochemical brain circuitry have unlocked a new mechanism of action by which arecoline-derived medications interact with dopaminergic processes to improve outcomes for schizophrenia patients. One such medication, xanomeline-trospium (Cobenfy), has emerged as the first such agent to receive U.S. Food and Drug Administration (FDA) approval for the treatment of schizophrenia and represents an entirely new class of pro-cholinergic medication within the field of psychiatry. Many in the field believe that this heralds the beginning of a new era of psychopharmacology: the era of muscarinic agonism. This article briefly described the fascinating journey from ancient betel nuts to modern muscarinic therapeutics.