Plant and Fungal Hallucinogens as Toxic and Therapeutic Agents

This chapter reviews hallucinogens of natural origin, covering indoleamines (e.g., psilocybin, ibogaine), phenylethylamines (mescaline), tropane alkaloids (atropine, scopolamine), cannabinoids (THC), and salvinorin A. It describes representative plants and mushrooms, their psychopharmacological effects, and sociocultural and historical use. The importance of set and setting in shaping consciousness-altering experiences is emphasized. The chapter discusses animal models for predicting hallucinogenic properties and investigating mechanisms of action. It compares hallucinogens to endogenous neurotransmitters, evaluates their ability to produce symptoms resembling mental disorders, and explores their therapeutic potential in psychopathological conditions.

Study at a glance

Abstract

This chapter aimed to provide an overview of the large number of hallucinogens of natural origin. Following a literature review, the following hallucinogens were selected for a detailed description that considered their essential chemical groups: indoleamines ( N,N -dimethyltryptamine, 5-methoxy- N,N -dimethyltryptamine, bufotenine, psilocybin, and ibogaine), phenylethylamines (mescaline), tropane alkaloids (atropine and scopolamine), cannabinoids (Δ^9-tetrahydrocannabinol), and a neoclerodane diterpenoid (salvinorin A). The following species were included as representative of each drug class: Mimosa tenuiflora , Psychotria viridis, Banisteriopsis caapi, Virola spp., Psilocybe spp., Tabernanthe iboga , Tabernaemontana spp., Lophophora spp., Trichocereus spp., Atropa belladonna , Brugmansia spp., Cannabis sativa , and Salvia divinorum , among others. In addition to psychopharmacological effects, this chapter aims to address the sociocultural and historical use of these hallucinogenic plants and mushrooms, along with the importance of both the set and the setting factors that affect the profound consciousness-altering effects of these compounds. Moreover, the use of animal models to predict the hallucinogenic properties of psychoactive plants and compounds and to investigate the mechanisms of action of psychodysleptic drugs is discussed. This chapter also attempts to establish a parallel between hallucinogens and endogenous neurotransmitters in humans, to compare the pharmacological and psychic action of these compounds, to evaluate hallucinogens’ ability to produce symptoms typical of certain mental disorders during their use, and to investigate the role of these compounds as therapeutic agents in several psychopathological conditions.