Ayahuasca and Psychosis
Dear Editor,

Ayahuasca is a botanical hallucinogenic beverage used by indigenous groups throughout the Northwestern Amazon. Active ingredients include the tryptamine hallucinogen DMT, and beta-carboline monoamine oxidase inhibitors which allow for oral activity of DMT.1 In Brazil, its use occurs also within syncretic religious organizations and its religious consumption is protected by law.2 In the last decades, religious use of ayahuasca has spread from South America to the United States and Europe. In these new environments, therapeutic and recreational use also occur.

Here we report the case of a young adult male, who experienced two psychotic paranoid episodes – separated by one year – during and after participation in ayahuasca rituals. Neither the subject, Mr. A, 21 years old at the time of his first episode, nor his parents had a history of psychosis. He had consumed other hallucinogens (LSD and psilocybin) on multiple occasions, and had been a nearly-daily marijuana smoker for the preceding six years with no significant adverse effects. At the time, he was obtaining graduate training in a Brazilian university. Before the first episode, he had already used ayahuasca “more or less twice per month, for about two years,” sometimes using marijuana concurrently, without incident.

During one particular ayahuasca ritual, he again combined its use with marijuana and experienced very intense paranoid and suicidal ideas – “these people are going to kill me in order to make me a human sacrifice;” “I will be operated upon and they will open my body;” “I have sinned and the spirits are persecuting me;” “I should kill myself right now before they do.” These feelings were so intense that he superficially cut himself with a sharp-edged ceremonial item during the ayahuasca ritual. Symptoms persisted for two to three weeks and resolved after treatment with risperidone, 6 mg daily, gradually being reduced to 0.5 mg daily. Treatment lasted approximately one year, during which time he did not use any psychoactives, and remained free of paranoid symptoms. After discontinuing risperidone, he resumed participation in ayahuasca rituals. During the third of these subsequent sessions, while not using concurrent marijuana, he again experienced similar paranoid and suicidal ideation, which persisted for another two to three weeks, which again responded well to a similar course of risperidone maintained for the next year.

Regular use of ayahuasca in research and naturalistic settings has not been routinely associated with psychopathological reactions.3 One literature review 4 reported that over a five-year period there were documented between 13 and 24 cases in which ayahuasca may have contributed to an undefined psychotic incident. These were reported from a cumulative estimated 25,000 ayahuasca sessions, and represent a rate less than 0.1% (0.052-0.096%). This is comparable to the incidence of transient psychoses reported by Cohen in his 1960 survey of researchers who had administered LSD in a controlled environment.5

Given the low incidence of, but potentially high morbidity associated with, transient drug-induced psychosis, both research and religious use of ayahuasca should be contraindicated in people with a history of psychosis.

Rafael G. dos Santos

BSc (Biol), MPsych (Behavioural Processes), PhD candidate (Pharmacol)

Interdisciplinary Group for Psychoactive Studies, Brazil.

Currently at: Centre d’Investigació de Medicaments, Institut de Recerca, Servei de Farmacologia Clínica, Hospital de la Santa Creu i Sant Pau (HSCSP), Barcelona, Spain.

Rick J. Strassman, MD

Department of Psychiatry, University of New Mexico School of Medicine, and Cottonwood Research Foundation, Taos, New Mexico, USA

Declaration of interest

We declare no conflict of interest.


1. McKenna DJ. Clinical investigations into the therapeutic potential of ayahuasca: rationale and regulatory challenges. Pharmacol Ther 2004; 102: 111-129.

2. Labate BC, Rose IS, Santos RG. Religiões ayahuasqueiras: um balanço bibliográfico. Mercado de Letras, 2008.

3. Dobkin de Rios M, Grob CS (eds.). Ayahuasca: cross-cultural perspectives. J Psychoactive Drugs 2005; 37.

4. Gable RS. Risk assessment of ritual use of oral dimethyltryptamine (DMT) and harmala alkaloids. Addiction 2007; 102: 24-34.

5. Cohen S. Lysergic acid diethylamide: side effects and complications. J Nerv Ment Dis 1960; 130: 30-40.

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