5-HT receptor in the context of "Antidepressant"

Lysergic acid diethylamide, commonly known as LSD (from German Lysergsäurediethylamid) and by the slang names acid and lucy, is a semisynthetic hallucinogenic drug derived from ergot, known for its powerful psychological effects and serotonergic activity. It was historically used in psychiatry and 1960s counterculture; it is currently legally restricted but experiencing renewed scientific interest and increasing use.

When taken orally, LSD has an onset of action within 0.4 to 1.0 hours (range: 0.1–1.8 hours) and a duration of effect lasting 7 to 12 hours (range: 4–22 hours). It is commonly administered via tabs of blotter paper. LSD is extremely potent, with noticeable effects at doses as low as 20 micrograms and is sometimes taken in much smaller amounts for microdosing. Despite widespread use, no fatal human overdoses have been documented. LSD is mainly used recreationally or for spiritual purposes. LSD can cause mystical experiences. LSD exerts its effects primarily through high-affinity binding to several serotonin receptors, especially 5-HT_2A, and to a lesser extent dopaminergic and adrenergic receptors. LSD reduces oscillatory power in the brain's default mode network and flattens brain hierarchy. At higher doses, it can induce visual and auditory hallucinations, ego dissolution, and anxiety. LSD use can cause adverse psychological effects such as paranoia and delusions and may lead to persistent visual disturbances known as hallucinogen persisting perception disorder (HPPD).

Ibogaine is a psychoactive indole alkaloid derived from plants such as Tabernanthe iboga, characterized by hallucinogenic and oneirogenic effects. Traditionally used by Central African foragers, it has undergone controversial research for the treatment of substance use disorders. Ibogaine exhibits complex pharmacology by interacting with multiple neurotransmitter systems, notably affecting opioid, serotonin, sigma, and NMDA receptors, while its metabolite noribogaine primarily acts as a serotonin reuptake inhibitor and κ-opioid receptor agonist.

The psychoactivity of the root bark of the iboga tree, T. iboga, one of the plants from which ibogaine is extracted, was first discovered by forager tribes in Central Africa, who passed the knowledge to the Bwiti tribe of Gabon. It was first documented in the 19th century for its spiritual use, later isolated and synthesized for its psychoactive properties, briefly marketed in Europe as a stimulant, and ultimately researched—and often controversial—for its potential in treating addiction despite being classified as a controlled substance.