Serotonergic psychedelics are being investigated in the treatment of various disorders and in the improvement of well-being. Evidence suggests that their subjective effects may play a role in long-term behavioral outcomes. The subjective effects are mediated by 5-HT2A receptor agonism, but the 5-HT1A receptor may also play a role in the subjective effects. This study elucidates the effects of...
The Hallucinogen Rating Scale (HRS) has been widely used to measure the subjective effects of psychedelics and other psychoactive substances. Its advantages include a basis in phenomenological interviews and clinical studies, straightforward items, and broad coverage of psychedelic effects. Previous studies have attempted to resolve its factor structure but were limited by small samples of...
We read with interest the study of ketamine psychedelic and analgesic effects by Olofsen et al.1 and the accompanying editorial by Mashour.2 In both articles, the authors refer to the “dissociative” effects of ketamine. Corssen and Domino3 originally used the term “dissociative” in 1966 to describe “patients and subjects who, during recovery from CI-581 [ketamine], felt as though they were in...
N,N-dimethyltryptamine (DMT), a psychedelic compound identified endogenously in mammals, is biosynthesized by aromatic-L-amino acid decarboxylase (AADC) and indolethylamine-N-methyltransferase (INMT). Whether DMT is biosynthesized in the mammalian brain is unknown. We investigated brain expression of INMT transcript in rats and humans, co-expression of INMT and AADC mRNA in rat brain and...
With an extreme range of terms for psychedelic drugsfrom "schizotoxic" to "entheogenic" -"psychedelic," nonetheless remains the most salient one.These substances manifest or disclose aspects of the mind of those who take them as well as the mind of those who study them.Proponents for the innumerable terms for these drugs are all able to adduce supportive evidence.Necessarily, this evidence is a...
Hoasca (also called ayahuasca) is a N,N-dimethyltryptamine (DMT) - containing psychedelic brew originally used for magico-religious purposes by Amerindian populations of the Amazon Basin. Recently, Brazilian syncretic churches have helped spread the ritual use of hoasca to Western societies. The aim of this study was to evaluate substance use, and neuropsychological and psychological...
The state of consciousness induced by N,N-dimethyltryptamine (DMT) is one of the most extraordinary of any naturally-occurring psychedelic substance. Users consistently report the complete replacement of normal subjective experience with a novel "alternate universe," often densely populated with a variety of strange objects and other highly complex visual content, including what appear to be...
Several lines of evidence suggest that classic (5HT2A agonist) hallucinogens have clinically relevant effects in alcohol and drug addiction. Although recent studies have investigated the effects of psilocybin in various populations, there have been no studies on the efficacy of psilocybin for alcohol dependence. We conducted a single-group proof-of-concept study to quantify acute effects of...
Three indole alkaloids that possess differing degrees of psychotropic/psychedelic activity have been reported as endogenous substances in humans; N,N-dimethyltryptamine (DMT), 5-hydroxy-DMT (bufotenine, HDMT), and 5-methoxy-DMT (MDMT). We have undertaken a critical review of 69 published studies reporting the detection or detection and quantitation of these compounds in human body fluids. In...
Ayahuasca is a psychedelic brew originally used for magico-religious purposes by Amerindian populations of the western Amazon Basin. Throughout the last four decades, the use of ayahuasca spread towards major cities in all regions of Brazil and abroad. This trend has raised concerns that regular use of this N,N-dimethyltryptamine- and harmala-alkaloid-containing tea may lead to mental and...
BACKGROUND: There is a growing scientific interest in the effects of hallucinogens in general and the religious use of psychoactive brew ayahuasca in Brazil in particular. However, there is not yet a standard instrument used in Brazil to evaluate the effects of hallucinogens. The Hallucinogen Rating Scale (HRS) is a questionnaire widely used in the U.S. and Europe to evaluate the effects of...
A direct injection/liquid chromatography-electrospray ionization-tandem mass spectrometry procedure has been developed for the simultaneous quantitation of 11 compounds potentially found in the increasingly popular Amazonian botanical medicine and religious sacrament ayahuasca. The method utilizes a deuterated internal standard for quantitation and affords rapid detection of the alkaloids by a...
The authors assessed 23 subjects immediately before and six months (27.5 weeks) after their first ayahuasca experience in an urban Brazilian religious setting, either Santo Daime (N = 15) or União do Vegetal (N = 8). Measures included scores on instruments assessing psychiatric symptoms, personality variables and quality of life. Independent variables were the frequency of ayahuasca use...
The use of the hallucinogenic brew ayahuasca, obtained from infusing the shredded stalk of the malpighiaceous plant Banisteriopsis caapi with the leaves of other plants such as Psychotria viridis, is growing in urban centers of Europe, South and North America in the last several decades. Despite this diffusion, little is known about its effects on emotional states. The present study...
Seventy detoxified heroin-addicted patients were randomly assigned to one of two groups receiving ketamine psychotherapy (KPT) involving two different doses of ketamine. The patients of the experimental group received existentially oriented psychotherapy in combination with a hallucinogenic ("psychedelic") dose of ketamine (2.0 mg/kg im). The patients of the control group received the same...
Tolerance of the behavioral effects of the short-acting, endogenous hallucinogen, N,N-dimethyltryptamine (DMT) is seen inconsistently in animals, and has not been produced in humans. The nature and time course of responses to repetitive, closely spaced administrations of an hallucinogenic dose of DMT were characterized. Thirteen experienced hallucinogen users received intravenous 0.3 mg/kg DMT...
A multinational, collaborative, biomedical investigation of the effects of hoasca (ayahuasca), a potent concoction of plant hallucinogens, was conducted in the Brazilian Amazon during the summer of 1993. This report describes the psychological assessment of 15 long-term members of a syncretic church that utilizes hoasca as a legal, psychoactive sacrament as well as 15 matched controls with no...
We generated dose-response data for the endogenous and ultra-short-acting hallucinogen, N,N-dimethyltryptamine (DMT), in a cohort of experienced hallucinogen users, measuring multiple biological and psychological outcome measures. Subjective responses were quantified with a new rating scale, the HRS, which provided better resolution of dose effects than did the biological variables. A tolerance...
Clinical research with hallucinogens has resumed after a generation's hiatus. To place these new studies in context, this article reviews the history of hallucinogens' use and abuse, discusses their pharmacological properties, and highlights previous human studies. Research with lysergic acid diethylamide and related hallucinogens with thousands of patients and control subjects was associated...
The use of naturally occurring and synthetically derived compounds for their "psychedelic" effects has been a part of human culture for thousands of years. The basic pharmacology of the major synthetic psychedelic compounds (primarily lysergic acid diethylamide [LSD]-25) is described and reference is made to their potentially beneficial psychological effects. Adverse reactions, defined as...