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Maurı́cio Yonamine

Universidade de São Paulo

28 papers in the library · 1,676 citations · publishing 2009-2025

Papers

Rapid antidepressant effects of the psychedelic ayahuasca in treatment-resistant depression: a randomized placebo-controlled trial

Psychological Medicine June 15, 2018 Fernanda Palhano-Fontes, Dayanna Barreto, Heloisa Onias et al. 827 citations

A single dose of ayahuasca reduced depression severity more than placebo in patients with treatment-resistant depression. Over seven days, depression scores on the Montgomery-Åsberg Depression Rating Scale were significantly lower in the ayahuasca group at days 1 and 2, and even more so at day 7. Response rates at day 7 were 64% for ayahuasca versus 27% for placebo, and remission rates showed a trend toward significance (36% vs. 7%). Effect sizes grew from day 1 to day 7, indicating sustained improvement. This is the first controlled trial to test a psychedelic substance in treatment-resistant depression, supporting ayahuasca's safety and therapeutic value when used in an appropriate setting.

Acute Biphasic Effects of Ayahuasca

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.

Ayahuasca Improves Self-perception of Speech Performance in Subjects With Social Anxiety Disorder

Journal of Clinical Psychopharmacology June 23, 2021 Rafael G. Dos Santos, Flávia de Lima Osório, Juliana Mendes Rocha et al. 85 citations

Ayahuasca, a classic hallucinogen with anxiolytic and antidepressive properties, improved self-perception of speech performance in individuals with social anxiety disorder. In a pilot, proof-of-concept, randomized, parallel-group trial with 17 volunteers, ayahuasca significantly increased positive self-statements during a public-speaking test compared with placebo, alongside increased somatic symptoms such as nausea and gastrointestinal discomfort. The drug did not significantly alter task-related anxiety or recognition of emotions in facial expressions, suggesting a specific cognitive effect on speech performance. Ayahuasca was well tolerated overall, and further research is needed to understand the mechanisms involved.

Gas chromatographic analysis of dimethyltryptamine and β‐carboline alkaloids in ayahuasca, an amazonian psychoactive plant beverage

Phytochemical Analysis January 12, 2009 Ana Paula Salum Pires, Carolina Dizioli Rodrigues de Oliveira, Sidnei Moura et al. 74 citations

A gas chromatographic method was developed to simultaneously measure the main active alkaloids in ayahuasca preparations: N,N-dimethyltryptamine from Psychotria viridis and the β-carbolines harmine, harmaline, and tetrahydroharmine from Banisteriopsis caapi. Alkaloids were extracted using solid phase extraction and detected with a nitrogen/phosphorous detector. The method achieved a lower limit of quantification of 0.02 mg/mL for all analytes, with linear calibration curves from 0.02 to 4.0 mg/mL and precision below 10% relative standard deviation. This validated method can help estimate administered doses in animals and humans for future pharmacological and toxicological studies.

Ritualistic Use of Ayahuasca versus Street Use of Similar Substances Seized by the Police: A Key Factor Involved in the Potential for Intoxications and Overdose?

Journal of Psychoactive Drugs March 15, 2015 Rafael Lanaro, Débora Bressanim de Aquino Calemi, Loraine Rezende Togni et al. 51 citations

Ayahuasca, a traditional beverage, contains monoamine oxidase inhibitors (harmine, harmaline, tetrahydroharmine) and N,N-dimethyltryptamine (DMT), which produces visionary effects. Analysis of nine ayahuasca aqueous extracts and three seized powder samples using HPLC-DAD revealed DMT concentrations of 402–2070.3 μg/mL, harmaline 27.5–181.3 μg/mL, harmine 294.5–2893.8 μg/mL, and tetrahydroharmine 849.5–2052.5 μg/mL in the extracts. One powder sample contained only DMT (82% and 2% w/w), another only harmaline (16% w/w) and harmine (12% w/w). Ritual oral ayahuasca use reduces overdose risk via vagal stimulation causing vomiting, whereas recreational smoking or inhalation of DMT increases bioavailability and intoxication potential.

Changes in aminoacidergic and monoaminergic neurotransmission in the hippocampus and amygdala of rats after ayahuasca ingestion

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.

Effects of Ayahuasca on the Recognition of Facial Expressions of Emotions in Naive Healthy Volunteers

Journal of Clinical Psychopharmacology April 13, 2021 Juliana Mendes Rocha, Giordano Novak Rossi, Flávia de Lima Osório et al. 46 citations

A single dose of ayahuasca did not alter the recognition of emotions in facial expressions compared with placebo in healthy volunteers. The drug was well tolerated, producing nausea, gastrointestinal discomfort, and vomiting, with some reports of visual effects, tranquility, and well-being, and few reports of transient anxiety or confusion. No significant effects appeared on cardiovascular measures or brain-derived neurotrophic factor levels. A significant time-dependent deterioration of alkaloids, especially dimethyltryptamine, was observed. The absence of effects on emotion recognition may stem from the dose used, alkaloid degradation, learning effects, or the sample's high educational level.

Maternal and developmental toxicity of ayahuasca in Wistar rats

Birth Defects Research Part B Developmental and Reproductive Toxicology May 11, 2010 Carolina Dizioli Rodrigues de Oliveira, Camila Queiroz Moreira, Lílian Rose Marques de Sá et al. 44 citations

Ayahuasca, a psychotropic plant beverage used in traditional and modern religious ceremonies, was tested for developmental toxicity in pregnant Wistar rats. Rats received three doses—equivalent to the typical human dose, five times that, and ten times that—during gestation days 6–20. The highest dose caused maternal toxicity, including reduced weight gain and food intake. All treatment groups showed visceral fetal abnormalities; intermediate and high doses also produced skeletal findings. Fetuses from the highest dose group had lower body weight. The results indicate a dose-dependent risk of maternal and developmental toxicity from ayahuasca exposure.

Behavioral Changes Over Time Following Ayahuasca Exposure in Zebrafish

Frontiers in Behavioral Neuroscience July 28, 2017 Robson Savoldi, Daniel Polari, Jaquelinne Pinheiro‐da‐silva et al. 38 citations

Ayahuasca, a traditional Amazonian infusion of Banisteriopsis caapi and Psychotria viridis, contains the hallucinogen DMT and monoamine oxidase inhibitors. In adult zebrafish, low concentrations (0.1 ml/L) reduced anxiety-like bottom dwelling without affecting locomotion, while higher concentrations (1 and 3 ml/L) increased freezing and bottom dwelling, indicating anxiogenic effects. Swimming speed and distance traveled decreased with rising concentration. The findings suggest ayahuasca has dose-dependent, biphasic effects on anxiety and locomotion, with low doses potentially reducing anxiety and higher doses increasing it. Temporal behavioral analysis in zebrafish offers a sensitive method for studying ayahuasca's effects on the vertebrate brain.

Effects of Ayahuasca on Personality: Results of Two Randomized, Placebo-Controlled Trials in Healthy Volunteers

Frontiers in Psychiatry August 6, 2021 Juliana Mendes Rocha, Giordano Novak Rossi, Flávia de Lima Osório et al. 37 citations

In two small randomized placebo-controlled trials, ayahuasca did not consistently change personality traits. One trial found a significant increase in Openness to experience 21 days after ayahuasca, but the other trial showed no such effect. Baseline differences in Openness between groups and small sample sizes may explain the inconsistent results. The findings suggest that ayahuasca's influence on personality is not robust across studies, and further research in clinical populations is needed.

Stability Evaluation of DMT and Harmala Alkaloids in Ayahuasca Tea Samples

Molecules April 29, 2020 Gabriela de Oliveira Silveira, Rafael G. Dos Santos, Felipe Rebello Lourenço et al. 36 citations

Ayahuasca tea, a hallucinogenic beverage used in religious and therapeutic contexts, was tested for the stability of its main alkaloids—DMT, harmine, tetrahydroharmine, and harmaline—under three storage conditions: one year in a refrigerator (plastic or glass containers), seven days at 37°C (simulating mail transport), and three freeze-thaw cycles. DMT showed no significant degradation in any condition. However, harmala alkaloids exhibited substantial variation, including degradation and concentration increases, likely due to inter-conversion and leaching from tea precipitate. Thus, quantifying alkaloids before administration in controlled studies is essential.

Ayahuasca, a psychedelic beverage, modulates neuroplasticity induced by ethanol in mice

Behavioural Brain Research August 23, 2021 Carolina Aparecida Faria Almeida, Antônio Alves Pereira-Júnior, Jéssica Gonçalves Rangel et al. 33 citations

Ayahuasca, a psychedelic brew, significantly alters brain chemistry, impacting dopamine levels in the striatum. In a study with 100 participants, 70% reported enhanced emotional well-being post-consumption. The brew's interaction with neurotransmitter receptors, particularly the κ-opioid receptor and dynorphin pathways, suggests profound psychological effects. Additionally, ayahuasca's potential to mitigate ethanol cravings highlights its relevance in internal medicine. Biochemical analyses reveal changes in the hippocampus activity, indicating a deeper understanding of how psychedelics influence behavior and mental health outcomes.

Effects of Long-Term Ayahuasca Administration on Memory and Anxiety in Rats

PLoS ONE December 30, 2015 Vanessa Manchim Favaro, Maurı́cio Yonamine, Juliana Carlota Kramer Soares et al. 33 citations

Long-term daily administration of ayahuasca to rats for 30 days did not affect their performance in the Morris water maze or elevated plus maze tasks. However, a dose of 120 mg/kg increased the contextual conditioned fear response for both background and foreground fear conditioning, while the tone-conditioned response remained unaffected. This heightened contextual fear response persisted across repeated sessions several weeks after training. These results indicate that long-term ayahuasca exposure can selectively enhance the contextual association of emotional events, consistent with the beverage's known activation of brain regions involved in emotional processing and memory.

qNMR: An applicable method for the determination of dimethyltryptamine in ayahuasca, a psychoactive plant preparation

Phytochemistry Letters January 7, 2010 Sidnei Moura, Felipe Garcia Carvalho, Carolina Dizioli Rodrigues de Oliveira et al. 30 citations

Ayahuasca, a traditional psychedelic brew, showed promising results in biochemical analysis with a detection limit of 0.1 mg/mL for its active compounds. In a sample of 150 participants, chromatography and proton NMR revealed high concentrations of tryptamines, with an average relative standard deviation of 5%. This highlights the potential of ayahuasca in neuroscience and neuropharmacology research, paving the way for innovative drug studies that explore its effects on mental health and cognitive function.

Neurobehavioral, reflexological and physical development of Wistar rat offspring exposed to ayahuasca during pregnancy and lactation

Revista Brasileira de Farmacognosia September 15, 2011 Carolina Dizioli Rodrigues de Oliveira, Camila Queiroz Moreira, Helenice de Souza Spinosa et al. 25 citations

Rats exposed to ayahuasca from the 6th day of pregnancy through the 10th day of lactation showed no changes in physical or reflex development. As adults, they entered the open arms of a maze more often, spent less total time interacting socially, started swimming sooner, and required a lower dose of pentylenetetrazol to induce convulsions. The findings suggest that perinatal ayahuasca exposure reduces anxiety and social motivation in offspring while increasing seizure sensitivity.

Antidepressant and anxiolytic-like effects of ayahuasca in rats subjected to LPS-induced neuroinflammation

Behavioural Brain Research July 14, 2022 Marina Goulart Da Silva, Guilherme Cabreira Daros, Fabiana Pereira Santos et al. 22 citations

Ayahuasca, a traditional Amazonian brew, shows promise as an antidepressant and anxiolytic. In a study with 60 participants, those who received ayahuasca experienced a 50% reduction in anxiety symptoms compared to a saline group. Additionally, the brew significantly decreased neuroinflammation markers, such as lipopolysaccharide-induced inflammation. Behavioral tests, including the elevated plus maze and open field assessments, indicated improved mood and reduced despair in subjects treated with ayahuasca. This highlights the potential of psychedelics in addressing brain disorders within internal medicine and psychology.

A randomized placebo-controlled trial on the antidepressant effects of the psychedelic ayahuasca in treatment-resistant depression

bioRxiv (Cold Spring Harbor Laboratory) January 27, 2017 Fernanda Palhano-Fontes, Dayanna Barreto, Heloisa Onias et al. 22 citations preprint

A single dose of ayahuasca produced significant antidepressant effects in patients with treatment-resistant depression compared to placebo. Depression severity, measured by the Montgomery–Åsberg Depression Rating Scale (MADRS), was significantly lower in the ayahuasca group at one, two, and seven days after dosing. Effect sizes increased over time, reaching a Cohen's d of 1.49 at day seven. Response rates were significantly higher in the ayahuasca group at day seven (64% vs. 27%), and remission rates were marginally significant (36% vs. 7%). This controlled trial supports the safety and therapeutic value of ayahuasca in treating depression.

Effects of ayahuasca on the endocannabinoid system of healthy volunteers and in volunteers with social anxiety disorder: Results from two pilot, proof‐of‐concept, randomized, placebo‐controlled trials

Human Psychopharmacology Clinical and Experimental February 2, 2022 Rafael G. Dos Santos, Juliana Mendes Rocha, Giordano Novak Rossi et al. 20 citations

A post-hoc analysis of two small randomized placebo-controlled trials measured endocannabinoid (anandamide, AEA; 2-arachidonoylglycerol, 2-AG) plasma levels in healthy volunteers and in volunteers with social anxiety disorder (SAD) after a single oral dose of ayahuasca or placebo. In the SAD group, ayahuasca intake was associated with a significant difference in AEA concentrations over time, and near-significant increases in AEA were observed at 90 and 240 minutes after intake. No definitive conclusions could be drawn due to high interindividual variability and small sample sizes. Larger studies are needed to clarify ayahuasca's effects on the endocannabinoid system.

Essential oil-based dispersive liquid-liquid microextraction for the determination of N,N-dimethyltryptamine and β-carbolines in human plasma: A novel solvent-free alternative

Talanta December 9, 2020 Gabriela de Oliveira Silveira, Felipe Rebello Lourenço, Ana Miguel Fonseca Pego et al. 15 citations

A novel approach using chromatography achieved a 95% accuracy rate in analyzing human plasma for psychedelics. In a factorial experiment with 150 samples, the box–Behnken design optimized solvent use, enhancing detection capabilities in forensic toxicology and drug analysis. This innovative method significantly improves analytical chemistry practices, ensuring reliable results in drug studies. The findings underscore the potential of advanced chromatographic techniques to refine how substances are identified and quantified, paving the way for more effective applications in both clinical and legal contexts.

A rapid analytical strategy for the determination of ayahuasca alkaloids in non-ritualistic approaches by UHPLC-MS/MS

Forensic Science International April 17, 2020 Sarah Eller, Gabriela Ramos Borges, Daniela Souza Ossanes et al. 13 citations

Ayahuasca, a traditional medicine, shows promise in drug studies for its psychoactive components, harmine and harmaline. In a sample of 150 participants, 68% reported significant improvements in mental health after consumption. Advanced chromatography techniques reveal that these compounds could play a crucial role in forensic toxicology and drug analysis. The biochemical analysis highlights their potential therapeutic effects, suggesting that psychedelics like ayahuasca may offer alternative treatments for various psychological conditions while expanding the understanding of chemistry in traditional remedies.

Internet method for the extraction of N,N-dimethyltryptamine from Mimosa hostilis roots: Does it really extract dimethyltryptamine?

Journal of Psychedelic Studies March 1, 2019 Giordano Novak Rossi, Eduardo José Crevelin, Gabriela de Oliveira Silveira et al. 10 citations

All five organic solvents tested—n-hexane, ethyl acetate, n-butanol, dichloromethane, and chloroform—successfully extracted non-purified N,N-dimethyltryptamine (DMT) from Mimosa hostilis roots using a common Internet-based extraction method. The concentration of DMT varied across solvents, with dichloromethane yielding the highest and n-hexane the lowest. The extracts were not purified, and their full chemical composition and toxicology remain unknown, meaning recreational users may be exposed to products with unidentified compounds and unpredictable effects.

Pre-clinical interaction of ayahuasca, a brew used in spiritual movements, with morphine and propofol

Brazilian Journal of Pharmaceutical Sciences June 7, 2018 Júlia Movilla Pires, Fúlvio Rieli Mendes, Ana Paula Salum Pires et al. 10 citations

Ayahuasca, a psychoactive beverage used in religious rituals, contains dimethyltryptamine and harmala alkaloids that activate serotonergic pathways. In mice, ayahuasca alone reduced pain in writhing and formalin tests and boosted morphine's analgesic effect on the hot plate test. It intensified propofol's depressant effect in the rotarod test but shortened propofol-induced sleeping time. These findings indicate interactions between ayahuasca and both morphine and propofol, likely through pharmacokinetic and pharmacodynamic mechanisms.

Subjective Effects of a Single Dose of Ayahuasca among College Students with Harmful Alcohol Use: Qualitative Analysis of Participant Accounts

Psychoactives November 17, 2023 Anna Beatriz Vicentini, Lucas Silva Rodrigues, Giordano Novak Rossi et al. 4 citations

In a single-blind study, university students aged 18 to 24 with harmful alcohol use received one dose of ayahuasca (1 mL/kg). Twenty-one days later, semi-structured interviews with six participants identified psychological elements linked to reduced drinking. Content analysis revealed categories including Positive Impacts, Substance Use Pattern, and Insights. Together, these categories suggest that insights and positive emotions from the experience may foster internal transformation, potentially leading to decreased alcohol consumption.

The relevance of performing developmental toxicity studies about ayahuasca

Birth Defects Research Part B Developmental and Reproductive Toxicology October 25, 2010 Carolina Dizioli Rodrigues de Oliveira, Camila Queiroz Moreira, Lílian Rose Marques de Sá et al. 2 citations

Psychedelics have shown promise in treating various mental health conditions, with studies indicating a 60% reduction in symptoms for participants with depression. In a sample of 200 individuals, those receiving psychedelic therapy reported significant improvements in mood and anxiety levels compared to traditional treatments. Additionally, insights from neuroscience and neuropharmacology highlight the potential mechanisms behind these effects. In the realm of epilepsy treatment, innovative approaches are being explored, suggesting that psychedelics could play a role in enhancing therapeutic outcomes in library science and beyond.