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.
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.