Journal of Psychopharmacology
October 27, 2026
José Augusto Silva Reis, Lara Zancaner Ueta, José Carlos Bouso et al.
This systematic review evaluates the relationship between classical psychedelic drugs (D-Lysergic acid N,N-diethylamide, psilocybin, ayahuasca/N-N-dimethyl-tryptamine, and mescaline) and the emergence of psychotic symptoms, aiming to synthesize evidence from contemporary studies (1984-2025) regarding the risk factors, prevalence, and clinical characteristics of psychosis related to psychedelic...
Journal of Clinical Psychopharmacology
October 19, 2026
Caio César De Paula, Anna Beatriz Vicentini, Lorena Terene Lopes Guerra et al.
Background: Observational studies with ritual ayahuasca users suggest that experienced users tend to have better cognitive performance, while novice users may experience transient impairments, particularly in working memory. However, no randomized clinical trials have systematically evaluated the cognitive effects of ayahuasca in healthy volunteers. Procedures: This double-blind, randomized,...
Journal of Clinical Psychopharmacology
September 18, 2026
Renan Massanobu Maekawa, Lorena T. L. Guerra, Bianca Villanova et al.
Background: Depressive and anxiety symptoms are highly prevalent among patients with cancer and are associated with substantial reductions in quality of life. However, effective therapeutic options remain limited. Ayahuasca, a serotonergic psychedelic traditionally used in Amazonian ritual contexts, has shown rapid antidepressant and anxiolytic effects following a single administration in...
Psychiatry and Clinical Neurosciences
May 30, 2026
Nathalia Novaretti, Rebeca Mendes P Pessoa, Jaime Eduardo Cecilio Hallak et al.
Oral ketamine has gained increasing interest beyond anesthesia, particularly for treatment-resistant depression, chronic pain, and pediatric procedural sedation. Despite expanding off-label use, there is no standardized pharmaceutical formulation, and long-term safety remains uncertain. A synthesis of evidence on safety and tolerability of the oral route is therefore needed to inform clinical...
Journal of Psychoactive Drugs
March 19, 2026
Pedro J. Teixeira, Jorge Encantado, Helena D Amaro et al.
Ayahuasca, a traditional Amazonian psychoactive brew, has gained increasing attention for its potential health benefits; however, no previous research has investigated its use in Portugal. This study aims to evaluate the health status, lifestyle behaviors, and psychosocial well-being of Portuguese ayahuasca users, comparing their self-reported health indicators with population norms. A...
European Archives of Psychiatry and Clinical Neuroscience
March 1, 2025
Arilton Martins Fonseca, Rafael Guimarães Dos Santos, Lívia Soman de Medeiros et al.
10 citations
Although several studies have been conducted to elucidate the relationship between psychedelic consumption and cognition, few have focused on understanding the long-term use influence of these substances on these variables, especially in ritualistic contexts. To verify the influence of ritualistic ayahuasca consumption on the cognition of experienced ayahuasca religious users (> 20 years) and...
CNS Spectrums
November 20, 2024
Rafael Guimarães Dos Santos, Jaime Eduardo Cecilio Hallak
13 citations
Ayahuasca is a botanical hallucinogen traditionally used for therapeutic and ritual purposes by indigenous groups from Northwestern Amazonian countries such as Brazil, Peru, Colombia, and Ecuador. Ayahuasca is made by the decoction of two plants, which are rich in the 5-HT1A/2A partial agonist dimethyltryptamine or DMT (from the leaves of the Psychotria viridis bush) and β-carbolines such as...
European Archives of Psychiatry and Clinical Neuroscience
October 28, 2024
Kaike Thiê da Costa Gonçalves, Vagner Deuel O de Tavares, Maria Luiza de Morais Barros et al.
5 citations
This systematic review aims to elucidate the nexus between ketamine's psychoactive properties and its efficacy in treating a broad spectrum of psychiatric disorders. We searched three databases and used citation tracking to include 29 studies. Predominantly, mood disorders, including bipolar disorder (BD) and major depressive disorder (MDD) (MDD + BD: + n = 25 studies), a large part of them...
Neuroscience & Biobehavioral Reviews
January 2020
Rafael Guimarães Dos Santos, Jaime Eduardo Cecilio Hallak
Serotoninergic hallucinogens include drugs such as lysergic acid diethylamide (LSD), dimethyltryptamine (DMT) and psilocybin. Recent trials with single/few doses of these compounds show that they induce rapid and sustained antidepressive, anxiolytic, and antiaddictive effects. These effects are also observed in religious groups using the DMT-containing brew ayahuasca. The agonist action of...
April 8, 2016
Beatriz Caiuby Labate, Rafael Guimarães Dos Santos, Brian T Anderson et al.
2 citations
This chapter presents a series of reflections on the therapeutic potential of the ritual use of ayahuasca in the treatment and handling of substance dependence problems. It reviews anthropological and psychiatric data on the ritual use of ayahuasca for 'healing' dependence in psychotherapeutic centers as well as in ayahuasca religions. The chapter discusses methodological, ethical and political...
Journal of Psychoactive Drugs
October 20, 2014
Rafael Guimarães Dos Santos
19 citations
Ayahuasca is a botanical hallucinogen traditionally used by indigenous groups of the northwest Amazon. In the last decade, the use of ayahuasca has spread from Brazil, Colombia, Ecuador, and Peru to the U.S., Europe, Asia, and Africa. Despite acute and long-term evidence of good tolerability and safety for ayahuasca administered in the laboratory or ritually consumed in religious contexts,...
Journal of Psychoactive Drugs
April 1, 2013
Rafael Guimarães Dos Santos
47 citations
Ayahuasca is a botanical hallucinogenic preparation traditionally consumed by Northwestern Amazonian indigenous groups. Scientific evidence suggests good tolerability after acute administration of ayahuasca and also after years or even decades of its ritual consumption. Nevertheless, some scientific and media reports associate ayahuasca or some of its alkaloids with severe intoxications. The...
Journal of Psychoactive Drugs
2013
Rafael Guimarães Dos Santos
87 citations
Despite being relatively well studied from a botanical, chemical, and (acute) pharmacological perspective, little is known about the possible toxic effects of ayahuasca (an hallucinogenic brew used for magico-ritual purposes) in pregnant women and in their children, and the potential toxicity of long-term ayahuasca consumption. It is the main objective of the present text to do an overview of...
SMAD Revista Eletrônica Saúde Mental Álcool e Drogas (Edição em Português)
February 1, 2007
Rafael Guimarães Dos Santos
7 citations
"Trata-se de uma revisão sobre as bases neuroquímicas e farmacológicas da ayahuasca,uma preparação psicoativa utilizada por vários grupos indígenas e não-indígenas comfinalidades terapêuticas, mágicas e religiosas."
Journal of Clinical Psychopharmacology
María Gómez-sousa, Daniel Jiménez‐garrido, Genís Ona et al.
24 citations
In recent decades, ritualistic use of ayahuasca has spread throughout the world. Retrospective studies have suggested a good psychological safety profile, but prospective studies involving ceremony ayahuasca-naive participants are lacking. We conducted the study using a subsample from a previous study, for which first-time ceremony ayahuasca participants were recruited. The subsample consisted...
Journal of Clinical Psychopharmacology
Lucas Silva Rodrigues, José Augusto Silva Reis, Giordano Novak Rossi et al.
8 citations
Ayahuasca is a South American plant hallucinogen rich in the psychedelic N,N-dimethyltryptamine and β-carbolines (mainly harmine). Preclinical and observational studies suggest that ayahuasca exerts beneficial effects in substance use disorders, but these potentials were never assessed in a clinical trial. Single-center, single-blind, feasibility, proof-of-concept study, assessing the effects...