Journal of Psychoactive Drugs
June 1, 2005
Evelyn Doering-Silveira, Charles S. Grob, Marlene Dobkin De Rios et al.
122 citations
Adolescents who use ayahuasca in a religious setting show similar lifetime drug use compared to those who never use it, but they consume significantly less alcohol. In the previous year, 46.31% of ayahuasca-using adolescents drank alcohol versus 74.4% of the comparison group; recent alcohol use was 32.5% versus 65.1%. The findings suggest religious affiliation may protect against alcohol use, and that early exposure to ayahuasca in a controlled ritual context does not lead to broader drug misuse.
PLoS One
September 30, 2015
Eduardo Ekman Schenberg, João Felipe Morel Alexandre, Renato Filev et al.
115 citations
Ayahuasca, an Amazonian plant-based brew used ritually in Brazil and increasingly worldwide, produces a two-phase brain effect. Electroencephalogram recordings and blood measurements of the brew's compounds (DMT, harmine, harmaline, tetrahydroharmine, and their metabolites) showed that 50 minutes after ingestion, alpha brainwave power (8–13 Hz) decreased, mostly in the left parieto-occipital cortex. Between 75 and 125 minutes, slow- and fast-gamma power (30–50 and 50–100 Hz, respectively) increased across multiple cortical regions, including left centro-parieto-occipital, left fronto-temporal, and right frontal areas. These brain changes were significantly linked to circulating levels of ayahuasca's active chemicals. The authors interpret these effects within cognitive and emotional frameworks relevant to ritual use and potential therapeutic applications.
Journal of Psychoactive Drugs
June 1, 2005
Dartiu Xavier Da Silveira, Charles S. Grob, Marlene Dobkin De Rios et al.
111 citations
Adolescents who consume ayahuasca in a religious setting show lower rates of anxiety, body dysmorphic concerns, and attentional problems compared to matched controls, despite similar overall psychiatric profiles. The study compared 40 adolescents from a Brazilian ayahuasca sect with 40 controls matched on sex, age, and education. Screening scales for depression, anxiety, alcohol abuse, attentional problems, and body dysmorphic disorders found considerably lower positive scores for anxiety, body dysmorphism, and attentional problems among ayahuasca-using adolescents. These low frequencies may reflect a protective effect of religious affiliation, though further research on other variables is needed.
Journal of psychopharmacology (Oxford, England)
November 1, 2014
Eduardo Ekman Schenberg, Maria Angélica de Castro Comis, Bruno Rasmussen Chaves et al.
110 citations
Ibogaine, an alkaloid used to treat drug dependence, is illegal in some countries but unregulated in Brazil, where it is combined with psychotherapy. A retrospective analysis of 75 former alcohol, cannabis, cocaine, and crack users (72% poly-drug users) found no serious adverse reactions or fatalities. 61% of participants remained abstinent. Those treated with ibogaine once reported a median abstinence of 5.5 months; those treated multiple times, 8.4 months. Both single and multiple treatments resulted in longer abstinence than before the first session. The findings suggest that physician-supervised ibogaine with psychotherapy can facilitate prolonged abstinence without fatalities, indicating it may be a safe and effective treatment for stimulant and other non-opiate drug dependence.
Comprehensive Psychiatry
November 1, 2016
Paulo César Ribeiro Barbosa, Rick J. Strassman, Dartiu Xavier Da Silveira et al.
104 citations
Regular ritual use of hoasca (ayahuasca) within a Brazilian religious group in the United States is associated with lower depression and confusion, higher agreeableness and openness, better memory performance, and less recent alcohol use compared to matched controls. The study of 30 members of the União do Vegetal and 27 non-user controls found no adverse effects on neuropsychological function. Lifetime hoasca use correlated with fewer physical health role limitations and less heavy alcohol use, suggesting the religious use of this psychedelic brew may have positive effects on mood and substance use.
World Journal of Biological Chemistry
January 1, 2013
Eduardo Ferreira de Castro-Neto, Rafael Henrique Da Cunha, Dartiu Xavier Da Silveira et al.
51 citations
In rats given ayahuasca by gavage at doses of 250, 500, or 800 mg/kg, the hippocampus showed increased levels of the inhibitory neurotransmitter GABA at all doses, while the amygdala showed decreased levels of the inhibitory amino acids glycine and GABA at the two higher doses. The amygdala also exhibited an increased utilization rate of the monoamines noradrenaline, dopamine, and serotonin at all three doses. These results suggest that ayahuasca ingestion increases inhibitory amino acid release in the hippocampus and increases monoamine turnover in the amygdala.
Journal of Psychedelic Studies
August 29, 2017
Eduardo Ekman Schenberg, Maria Angélica de Castro Comis, João Felipe Morel Alexandre et al.
39 citations
Patients with substance-related disorders who received ibogaine in a treatment program reported intense physical discomfort and a psychologically challenging experience, along with heightened memory retrieval—especially about past drug use—and vivid, dreamlike visions. The experience shared some features with other psychedelics but also differed markedly. The authors propose that ibogaine's subjective effects may function as simulations of threat and danger, drawing on an evolutionary theory of dreaming.
Journal of Psychedelic Studies
April 1, 2017
Eduardo Ekman Schenberg, Maria Angélica de Castro Comis, João Felipe Morel Alexandre et al.
29 citations
A treatment combining the psychedelic alkaloid ibogaine with cognitive-behavioral therapy led to improvements in craving, personal relationships, quality of life, and self-efficacy among people with substance use disorders, including cocaine dependence. These secondary outcomes were assessed through semi-structured interviews and qualitative content analysis. The findings support the therapeutic potential of ibogaine-assisted psychotherapy for treating substance use disorders, particularly for psychostimulants like cocaine and crack cocaine, for which effective treatments are lacking.
Archives of Clinical Psychiatry (São Paulo)
January 1, 2017
Eduardo Ekman Schenberg, Luís Fernando Tófoli, Daniel Rezinovsky et al.
28 citations
A Brazilian Portuguese version of the States of Consciousness Questionnaire (SOCQ) was produced, and the 30-item Mystical Experience Questionnaire (MEQ30) was validated in a sample of 1,504 Portuguese-speaking respondents who completed an online survey. Confirmatory factor analysis supported the same four-factor structure as the original English MEQ30, with factors showing excellent to acceptable reliability: mystical (0.95), positive mood (0.71), transcendence of time/space (0.83), and ineffability (0.81). The availability of these instruments allows systematic cross-cultural research on altered states of consciousness and mystical experiences in the Brazilian Portuguese-speaking population.
Archives of Clinical Psychiatry (São Paulo)
January 1, 2011
Suely Mizumoto, Dartiu Xavier Da Silveira, Paulo César Ribeiro Barbosa et al.
14 citations
A Brazilian Portuguese version of the Hallucinogen Rating Scale (HRS) has been produced through translation, back-translation, and committee review, following guidelines for semantic and conceptual equivalence. The HRS is a standard questionnaire used in the U.S. and Europe to evaluate subjective effects of hallucinogens, including ayahuasca. The final version is intended to provide a sensitive instrument for quantifying hallucinogen-induced states in Brazil, where scientific interest in such substances is growing.
Journal of Psychopharmacology
June 26, 2026
Flavia Giaffone de Paiva Ferreira, João Ariel Bonar Fernandes, Renato Filev et al.
A scoping review categorized psychosocial protocols used in psychedelic research for mental health treatment. Seven categories were defined, reflecting distinct emphases on the substance, participant, research team, and sociocultural context. Although limited reporting and heterogeneity remain methodological challenges, the proposed parameters suggest a shared language to describe, compare, and examine psychosocial protocols across studies, reducing conceptual uncertainty. The review may facilitate research decision-making and support structured, replicable study designs while allowing flexibility for individualized and culturally responsive care. Explicitly defining the intended purpose of psychosocial protocols could improve transparent reporting and evaluation.
European Psychiatry
January 1, 2010
Evelyn Doering-Silveira, Enrique Lopez, Charles S. Grob et al.
Adolescents who consume ayahuasca in a religious ritual setting perform well on neuropsychological tests, but not as well as non-using peers on complex tasks that require more cognitive functions. The study compared 40 ayahuasca-using adolescents with 40 matched controls. Both groups performed well overall, but controls outperformed users on the more demanding tests. The authors suggest ayahuasca may have subtle effects on cognition observable only during highly demanding tasks, while noting that other variables could have influenced the results.