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The potent hallucinogen N,N-dimethyltryptamine (DMT) has garnered significant interest in recent years due to its profound effects on consciousness and its therapeutic psychopotential. DMT is an integral (but not exclusive) psychoactive alkaloid in the Amazonian plant-based brew ayahuasca, in which admixture of several β-carboline monoamine oxidase A (MAO-A) inhibitors potentiate the activity of oral DMT, while possibly contributing in other respects to the complex psychopharmacology of ayahuasca. Irrespective of the route of administration, DMT alters perception, mood, and cognition, presumably through agonism at serotonin (5-HT) 1A/2A/2C receptors in brain, with additional actions at other receptor types possibly contributing to its overall psychoactive effects. Due to rapid first pass metabolism, DMT is nearly inactive orally, but co-administration with β-carbolines or synthetic MAO-A inhibitors (MAOIs) greatly increase its bioavailability and duration of action. The synergistic effects of DMT and MAOIs in ayahuasca or synthetic formulations may promote neuroplasticity, which presumably underlies their promising therapeutic efficacy in clinical trials for neuropsychiatric disorders, including depression, addiction, and post-traumatic stress disorder. Advances in neuroimaging techniques are elucidating the neural correlates of DMT-induced altered states of consciousness, revealing alterations in brain activity, functional connectivity, and network dynamics. In this comprehensive narrative review, we present a synthesis of current knowledge on the pharmacology and neuroscience of DMT, β-carbolines, and ayahuasca, which should inform future research aiming to harness their full therapeutic potential. [ABSTRACT FROM AUTHOR]

Recent research into so-called psychedelic substances, such as psilocybin, ketamine, and mescaline analogues, has been hailed as a "renaissance" heralding a "paradigm shift" in psychiatry. There is hope that psychedelic-assisted therapy will be made more available to address mental and substance use health problems through existing systems of medicalization and legalization. There are important relational and epistemic concerns that must be addressed, however, before we might begin stewarding this class of substances into the medical landscape in a responsible, evidence-based manner. In this paper, we draw on our ethnographic and clinical research observations to argue that the ontological and relational commitments of traditional medicine (ayahuasca-related healing) and randomized controlled trial (RCT) (ketamine-assisted psychotherapy) practices have important and revealing overlaps; together, they bring attention to ideal ways of working with these substances, as well as to ideal forms of healthcare more generally, with implications for reimagining our healthcare system from the ground up. As such, more is needed than a circumscribed shift to a new epistemological orientation ("paradigm"). We conclude by promoting ideals in alignment with our data and observations—relationality, inter-being, and epistemological fluidity—and by exploring how these ideals might reshape the medical landscape. [ABSTRACT FROM AUTHOR]

Rationale: To uncover whether psychedelic drugs attenuate fear memory responses would advance the development of better psychedelic-based treatments for posttraumatic stress disorder (PTSD). Ayahuasca (AYA), a psychedelic brew containing indolamine N, N-dimethyltryptamine (DMT) and β-carbolines, facilitates fear extinction and improves neural plasticity. Upon retrieval, fear memory undergoes labilization and reconsolidation; however, the effects of AYA on this memory stabilization phase are unknown. Objectives: We aimed to investigate the effects of AYA treatment on fear memory reconsolidation. Methods: Fear-conditioned Wistar rats received AYA (60, 120, or 240 mg/kg) or H2O orally via gavage o.g. 20 min before, immediately, or 3 h after a short retrieval session. Analysis of AYA through liquid chromatography-tandem mass spectrometry was used to determine the content of DMT and β-carbolines in AYA. Results: AYA impaired fear memory reconsolidation when given 20 min before or 3 h after memory retrieval, with the dose of 60 mg/kg being effective at both moments. This dose of AYA was devoid of anxiolytic effect. Importantly, during retrieval, AYA did not change fear expression. The lack of retrieval abolished the reconsolidation impairing effect of AYA. The effects of AYA treatment 20 min before or 3 h after memory retrieval lasted at least 22 days, suggesting no spontaneous recovery of fear memory. Fear memory impairments induced by AYA treatment, at both moments, do not show reinstatement. Conclusions: Our findings support the view that a low dose of AYA treatment impairs early and late stages of memory reconsolidation instead of facilitating fear extinction. [ABSTRACT FROM AUTHOR]

Ayahuasca is a hallucinogenic/psychedelic traditionally used for ritual and therapeutic purposes. One such therapeutic use is related to Substance Use Disorders (SUDs). A previous systematic review of preclinical and human studies published until 2016 suggested that ayahuasca and its alkaloids have therapeutic effects in the treatment of SUDs. To conduct an update of this previous review. A systematic review of quantitative studies which analyzed the effects of ayahuasca and its alkaloids on drug use (primary outcome) and other measures (secondary outcomes) related to SUDs was conducted, including articles from 2016 to 2020. Nine studies (four preclinical, five observational) were included in the review. Preclinical studies in rodents reported reductions in amphetamine self-administration and anxiety, and in alcohol- and methylphenidate-induced conditioned place preference. Observational studies among healthy ritual ayahuasca users and patients with SUDs reported reductions in drug use, anxiety, and depression, and increases in quality of life and well-being. We replicated the findings of the previous review suggesting that ayahuasca and its alkaloids have therapeutic effects in the treatment of SUDs. However, translation of preclinical data to humans is limited, observational studies do not allow us to infer causality, and there is a lack of standardization on ayahuasca doses. Although promising, randomized, controlled trials are needed to better elucidate these results. The PROSPERO ID for this study is CRD42020192046. [ABSTRACT FROM AUTHOR]

Rationale and objectives: Differences among psychedelic substances regarding their subjective experiences are clinically and scientifically interesting. Quantitative linguistic analysis is a powerful tool to examine such differences. This study compared five psychedelic substance report groups and a non-psychedelic report group on quantitative linguistic markers of psychological states and processes derived from recreational use-based online experience reports. Methods: Using 2947 publicly available online reports, we compared Ayahuasca and N,N-dimethyltryptamine (DMT, analyzed together), ketamine, lysergic acid diethylamide (LSD), 3,4-methylenedioxymethamphetamine (MDMA), psilocybin (mushroom), and antidepressant drug use experiences. We examined word frequencies related to various psychological states and processes and semantic proximity to psychedelic and mystical experience scales. Results: Linguistic markers of psychological function indicated distinct effect profiles. For example, MDMA experience reports featured an emotionally intensifying profile accompanied by many cognitive process words and dynamic-personal language. In contrast, Ayahuasca and DMT experience reports involved relatively little emotional language, few cognitive process words, increased analytical thinking-associated language, and the most semantic similarity with psychedelic and mystical experience descriptions. LSD, psilocybin mushroom, and ketamine reports showed only small differences on the emotion-, analytical thinking-, psychedelic, and mystical experience-related language outcomes. Antidepressant reports featured more negative emotional and cognitive process-related words, fewer positive emotional and analytical thinking-related words, and were generally not similar to mystical and psychedelic language. Conclusion: This article addresses an existing research gap regarding the comparison of different psychedelic drugs on linguistic profiles of psychological states, processes, and experiences. The large sample of experience reports involving multiple psychedelic drugs provides valuable information that would otherwise be difficult to obtain. The results could inform experimental research into psychedelic drug effects in healthy populations and clinical trials for psychedelic treatments of psychiatric problems. [ABSTRACT FROM AUTHOR]

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 beginners (< 3 years), which participated in rituals of the Centro Luz Divina (CLD), a Santo Daime church in Brazil. Observational, descriptive, and cross-sectional study was carried out in which 48 people participated divided into three groups: (a) experienced ayahuasca users (n = 16), (b) beginner ayahuasca users (n = 16) and (c) control group (n = 16). All groups were matched by sex, age, and education and contained 8 women and 8 men. Cognition was assessed with the WASI (intelligence quotient), Digit Span (verbal working memory), Corsi Block-Tapping Task (visuospatial-related and working memory), Rey–Osterrieth Complex Figure test (visual perception, immediate memory), and Wisconsin Card Sorting and Five Digit Test (executive functions). Groups were homogenous in terms of sociodemographic characteristics, with participants presenting average intellectual performance. There was no evidence of cognitive decline amongst ayahuasca users. The experienced group showed higher scores compared to the less experienced group in the Digit Span and Corsi Block-Tapping tasks, which assess working verbal and visuospatial memories respectively. We confirmed the botanical identities of Psychotria viridis and Banisteriopsis caapi and the presence of the alkaloids both in the plants and in the brew. Short and long-term ayahuasca consumption does not seem to alter human cognition, while long-term use seems to be associated with improvements in aspects of working memory when compared with short-term use. [ABSTRACT FROM AUTHOR]

Ayahuasca is a plant concoction containing N,N-dimethyltryptamine (DMT) and certain β-carboline alkaloids from South America. Previous research in naturalistic settings has suggested that ingestion of ayahuasca can improve mental health and well-being; however, these studies were not placebo controlled and did not control for the possibility of expectation bias. This naturalistic observational study was designed to assess whether mental health changes were produced by ayahuasca or by set and setting. Assessments were made pre- and post-ayahuasca sessions in 30 experienced participants of ayahuasca retreats hosted in the Netherlands, Spain, and Germany. Participants consumed ayahuasca (N = 14) or placebo (N = 16). Analysis revealed a main effect of time on symptoms of depression, anxiety, and stress. Compared to baseline, symptoms reduced in both groups after the ceremony, independent of treatment. There was a main treatment × time interaction on implicit emotional empathy, indicating that ayahuasca increased emotional empathy to negative stimuli. The current findings suggest that improvements in mental health of participants of ayahuasca ceremonies can be driven by non-pharmacological factors that constitute a placebo response but also by pharmacological factors that are related to the use of ayahuasca. These findings stress the importance of placebo-controlled designs in psychedelic research and the need to further explore the contribution of non-pharmacological factors to the psychedelic experience. [ABSTRACT FROM AUTHOR]

The present study examines the association between the ceremonial use of ayahuasca—a decoction combining the Banistereopsis caapi vine and N,N-Dimethyltryptamine-containing plants—and changes in personality traits as conceived by the Five-Factor model (FFM). We also examine the degree to which demographic characteristics, baseline personality, and acute post-ayahuasca experiences affect personality change. Participants recruited from three ayahuasca healing and spiritual centers in South and Central America (N = 256) completed self-report measures of personality at three timepoints (Baseline, Post, 3-month Follow-up). Informant-report measures of the FFM were also obtained (N = 110). Linear mixed models were used to examine changes in personality and the moderation of those changes by covariates. The most pronounced change was a reduction in Neuroticism dzself-reportT1–T2 = − 1.00; dzself-reportT1–T3 = −.85; dzinformant-reportT1–T3 = −.62), reflected in self- and informant-report data. Moderation of personality change by baseline personality, acute experiences, and purgative experiences was also observed. [ABSTRACT FROM AUTHOR]

The consumption of ayahuasca, a brew prepared from the decoction of two Amazon plants, has increased worldwide in the last decades. This fact raised questions about the safety in its oral administration. In this sense, information concerning the chemical composition of ayahuasca is essential to find a comprehensive reply. Therefore, the aim of this study consisted of determining the elemental composition of ready-to-consume ayahuasca samples produced in Brazil, in order to evaluate the safety in the oral administration of this beverage, considering recommended macroelement and microelement daily intake values and the permitted limits of potentially toxic heavy metals. Real ayahuasca samples, obtained from Brazilian religious groups, underwent microwave radiation-assisted acid decomposition, and Li, Al, Mn, Fe, Co, Cu, Zn, As, Cd, Hg, and Pb concentrations were determined by ICP-MS, while Ca, Mg, K, and P concentrations were determined by ICP OES. Method accuracy was assessed by analyte addition and recovery assays. Recoveries ranged from 80 and 118%, indicating satisfactory accuracy. Limit of detection (LOD) and limit of quantification (LOQ) values were lower than 1 mg L−1 for the macroelements determined by ICP OES and lower than 3.5 μg L−1 for the microelements determined by ICP-MS. The concentrations of the elements determined in the samples were lower than the recommended or tolerable limits; hence, it is possible to affirm that ayahuasca presents safe administration levels regarding total elemental content. [ABSTRACT FROM AUTHOR]

Rationale: Major depressive disorder is one of the leading global causes of disability, for which the classic serotonergic psychedelics have recently reemerged as a potential therapeutic treatment option. Objective: We present the first meta-analytic review evaluating the clinical effects of classic serotonergic psychedelics vs placebo for mood state and symptoms of depression in both healthy and clinical populations (separately). Results: Our search revealed 12 eligible studies (n = 257; 124 healthy participants, and 133 patients with mood disorders), with data from randomized controlled trials involving psilocybin (n = 8), lysergic acid diethylamide ([LSD]; n = 3), and ayahuasca (n = 1). The meta-analyses of acute mood outcomes (3 h to 1 day after treatment) for healthy volunteers and patients revealed improvements with moderate significant effect sizes in favor of psychedelics, as well as for the longer-term (16 to 60 days after treatments) mood state of patients. For patients with mood disorder, significant effect sizes were detected on the acute, medium (2–7 days after treatment), and longer-term outcomes favoring psychedelics on the reduction of depressive symptoms. Conclusion: Despite the concerns over unblinding and expectancy, the strength of the effect sizes, fast onset, and enduring therapeutic effects of these psychotherapeutic agents encourage further double-blind, placebo-controlled clinical trials assessing them for management of negative mood and depressive symptoms. [ABSTRACT FROM AUTHOR]

Rationale: Suicidality is a major public health concern with limited treatment options. Accordingly, there is a need for innovative interventions for suicidality. Preliminary evidence indicates that treatment with the psychedelic ayahuasca may lead to decreases in depressive symptoms among individuals with major depressive disorder (MDD). However, there remains limited understanding of whether ayahuasca also leads to reductions in suicidality. Objective: To examine the acute and post-acute effect of ayahuasca on suicidality among individuals with MDD. Methods: We conducted a secondary analysis of an open-label trial in which individuals with recurrent MDD received a single dose of ayahuasca (N = 17). Suicidality was assessed at baseline; during the intervention; and 1, 7, 14, and 21 days after the intervention. Results: Among individuals with suicidality at baseline (n = 15), there were significant acute (i.e., 40, 80, 140, and 180 min after administration) and post-acute (1, 7, 14, and 21 days after administration) decreases in suicidality following administration of ayahuasca. Post-acute effect sizes for decreases in suicidality were large (Hedges' g = 1.31–1.75), with the largest effect size 21 days after the intervention (g = 1.75). Conclusions: When administered in the appropriate context, ayahuasca may lead to rapid and sustained reductions in suicidality among individuals with MDD. Randomized, double-blind studies with larger sample sizes are needed to confirm this early finding. [ABSTRACT FROM AUTHOR]

Rationale: Accumulating evidence suggests that ayahuasca, a hallucinogenic beverage used in traditional Amazonian communities for ritualistic and curative purposes, has been associated with reduced rates of substance use disorders. However, the brain mechanisms underlying the therapeutic effects of ayahuasca have not yet been fully elucidated. Objectives: The aim of the present study was to investigate the effects of treatment with ayahuasca on the rewarding properties of the psychostimulant methylphenidate. Methods: The rewarding properties of ayahuasca (100 mg/kg, orally) and methylphenidate (10 mg/kg, i.p.) were investigated using the conditioned place preference (CPP) model. Furthermore, we evaluated the effects of repeated treatment with ayahuasca on the reinstatement of methylphenidate-induced CPP. Fos expression was evaluated in different limbic structures (cingulate cortex—area 1, prelimbic cortex, infralimbic cortex, orbitofrontal cortex—lateral orbital area, nucleus accumbens core and shell, ventral tegmental area, dorsal striatum, and basolateral amygdala) upon each experimental phase. Results: Both ayahuasca and methylphenidate induced CPP in mice. However, ayahuasca had limited effects on Fos expression, while methylphenidate altered Fos expression in several brain regions associated with the behavioral effects of drugs of abuse. Treatment with ayahuasca after conditioning with methylphenidate blocked the reinstatement of methylphenidate-induced CPP. Those behavioral effects were accompanied by changes in Fos expression patterns, with ayahuasca generally blocking the changes in Fos expression induced by conditioning with methylphenidate and/or reexposure to methylphenidate. Conclusions: Our findings suggest that ayahuasca restored normal brain function in areas associated with the long-term expression of drug wanting/seeking in animals conditioned to methylphenidate. [ABSTRACT FROM AUTHOR]

Ayahuasca is a psychoactive plant brew containing dimethyltryptamine (DMT) and monoamine oxidase inhibitors (MAOIs). It originates from the Amazon basin, where it is used primarily for ceremonial purposes. Ayahuasca tourists are now entering certain communities seeking alternative physical or psychological healing, as well as spiritual growth. Rationale: Recent evidence has shown that the similar acting psychedelic compound, psilocybin, facilitated long-term increases in trait openness following a single administration. Objectives: This paper assesses the impact of ayahuasca on personality in a traditional framework catering for ayahuasca tourists. Method: Within a mixed design, we examined the effect of ayahuasca on participants' personality (measured by the NEO Personality Inventory 3 questionnaire) across time (pre- to post-ayahuasca administration, and 6-month follow-up), relative to a comparison group (who did not ingest ayahuasca). Results: The results demonstrated significant increases in agreeableness pre- and post-ayahuasca administration and significant reductions in neuroticism in 24 participants, relative to the comparison group. Both of these changes were sustained at 6-month follow-up, and trait level increases were also observed in openness at this stage. Additionally, greater perceived mystical experience (measured using the Mystical Experience Questionnaire 30) was associated with increased reductions in neuroticism. Conclusions: These findings, which indicate a positive mediating effect of ayahuasca on personality, support the growing literature suggesting potential therapeutic avenues for serotonergic psychedelics. [ABSTRACT FROM AUTHOR]

Ayahuasca is a hallucinogenic beverage that affects the serotonergic system and have therapeutic potential for many diseases and disorders, including depression and drug addiction. The objectives of this study were to evaluate the potential toxic effects of ayahuasca on rats after chronic exposure, and the levels of monoamines, their metabolites and the brain-derived neurotrophic factor (BDNF) in the brain. Female and male rats were treated orally for 28 days with H2O (control), fluoxetine (FLX), a selective serotonin reuptake inhibitor antidepressant, or ayahuasca (Aya) at doses of 0.5X, 1X and 2X the ritualistic dose (7 to 10 animals/group). Clinical, hematological and macroscopic results showed that ayahuasca was safe to the rats. Behavior tests conducted one hour after the last treatment showed that male rats from the Aya1 group explored the open field central area less than the control group, and the number of entries in the central area compared to total locomotion was also significantly lower in this group and in the FLX group. The hippocampus was removed for BDNF analysis and the remaining brain was used for monoamine analysis by HPLC-FL. Serotonin levels were significantly higher than control only in the Aya2 female group, while a significant reduction of its metabolite 5-HIAA was observed in the FLX group. Dopamine levels were similar among the experimental groups, but the levels of its metabolite DOPAC increased significantly in the Aya1 and Aya2 groups compared to controls, especially in females, and the DOPAC/dopamine turnover was significantly higher in Aya2 group. The levels of HVA, another dopamine metabolite, did not change with the treatments compared to controls, but HVA/DOPAC ratio was significantly lower in all ayahuasca male groups. Norepinephrine was not detected in any brain sample, and the levels of its metabolite MHPG did not change significantly among the groups. BDNF levels in the hippocampus were significantly higher in the FLX and Aya2 female groups compared to controls when expressed in relation to the total brain weight. The mechanisms involved in the increase in serotonin, dopamine turnover and BDNF levels observed in ayahuasca treated animals should be further investigated in specific brain areas. [ABSTRACT FROM AUTHOR]

Rationale: There is a growing body of evidence demonstrating the therapeutic potential of ayahuasca for treating depression and anxiety. However, the mechanisms of action involved in ayahuasca's therapeutic effects are unclear. Mindfulness and cognitive flexibility may be two possible psychological mechanisms. Like other classic psychedelics, ayahuasca also leads to an 'afterglow' effect of improved subjective well-being that persists after the acute effects have subsided. This period may offer a window of increased therapeutic potential. Objective: To explore changes in mindfulness and cognitive flexibility before and within 24 h after ayahuasca use. Methods: Forty-eight participants (54% female) were assessed on measures of mindfulness (Five Facets Mindfulness Questionnaire (FFMQ)), decentering (Experiences Questionnaire (EQ)), and cognitive flexibility (Cognitive Flexibility Scale (CFS)), and completed the Stroop and Wisconsin Picture Card Sorting Task (WPCST) before drinking ayahuasca, and again within 24 h. Results: Mindfulness (FFMQ total scores and four of the five mindfulness facets: observe, describe, act with awareness, and non-reactivity) and decentering (EQ) significantly increased in the 24 h after ayahuasca use. Cognitive flexibility (CFS and WPCST) significantly improved in the 24 h after ayahuasca use. Changes in both mindfulness and cognitive flexibility were not influenced by prior ayahuasca use. Conclusions: The present study supports ayahuasca's ability to enhance mindfulness and further reports changes in cognitive flexibility in the 'afterglow' period occur, suggesting both could be possible psychological mechanisms concerning the psychotherapeutic effects of ayahuasca. Given psychological gains occurred regardless of prior ayahuasca use suggests potentially therapeutic effects for both naïve and experienced ayahuasca drinkers. [ABSTRACT FROM AUTHOR]

Rationale: Recent studies have assessed the therapeutic potential of ayahuasca for the treatment of depression with promising preliminary results. Objectives: Here, we examine the course of grief over 1 year of follow-up in a bereaved sample that attended a center in Peru to participate in indigenous Shipibo ayahuasca ceremonies. We also explore the roles of experiential avoidance and decentering as mechanisms of change. Methods: Bereaved participants who attended the ayahuasca center responded to an online survey that included the Texas Revised Inventory of Grief, Symptom Assessment-45, WHO Quality of Life-Bref, Acceptance and Action Questionnaire, and Decentering. Baseline assessment was completed by 50 individuals (T0). Of these, 39 completed the post-assessment at 15 days (T1), 31 at 3 months (T2), 29 at 6 months (T3), and 27 at 12 months (T4) after leaving the retreat. Pearson's analysis was performed to examine the relationship between the severity of grief and mechanisms of change during the period of T0 and T1. Results: A significant decrease in Texas Revised Inventory was observed at all time points (T1: Cohen's d = 0.84; T2: Cohen's d = 1.38; T3: Cohen's d = 1.16; T4: Cohen's d = 1.39). We found a relationship between experiential avoidance (r = 0.55; p <.01), decentering (r = − 0.47; p <.01), and a reduction in the severity of grief. Conclusions: Our results suggest that the ceremonial use of ayahuasca has therapeutic value by reducing the severity of grief. Acceptance and decentering are both psychological processes that mediate the improvement of grief symptoms. [ABSTRACT FROM AUTHOR]

Ayahuasca is a hallucinogenic decoction used as a traditional medicine in several Amazonian regions. The ritualistic use of ayahuasca has spread throughout many countries, making it necessary to study its risks and benefits. Two sub-studies were designed for this investigation. In sub-study 1, a psychiatric interview and a battery of questionnaires were administered to subjects (n = 40) before their first ayahuasca use. Two follow-ups were conducted at 1 and 6 months. In sub-study 2, the same interview and battery of questionnaires were administered to long-term ayahuasca users (n = 23) and their scores were compared with those of the ayahuasca-naïve group. In the first assessment, nearly half (45%) of the naïve users were found to meet the diagnostic criteria for a psychiatric disorder. After the ayahuasca use, more than 80% of those subjects showed clinical improvements that persisted at 6 months. The questionnaires showed significant reductions in depression and psychopathology. Regarding sub-study 2, long-term users showed lower depression scores, and higher scores for self-transcendence and quality of life, as compared to their peers in sub-study 1. Further controlled and observational naturalistic studies assessing the eventual risks and potential benefits of ayahuasca are warranted. [ABSTRACT FROM AUTHOR]

Ayahuasca (caapi, yajé), is a psychoactive brew from the Amazon Basin region of South America traditionally considered a "master plant." It is prepared as a decoction from Banisteriopsis caapi and Psychotria viridis, which it is thought that it stimulates creative thinking and visual creativity. Native healers of the Orinoco and Amazon basins have used traditionally ayahuasca as a healing tool for multiple purposes, particularly to treat psychological disorders in the patients, with some beneficial effects experimentally and clinically validated. Recently, several syncretic religions, as the "União de Vegetal" (UDV) group in Brazil, have been spread around the world. The use of ayahuasca has been popularized by internet and smart-shops, bringing the psychoactive substance to new highs, emerging new "ayahuasqueros." Ayahuasca has alkaloids as β-carbolines and dimethyltryptamines, which inhibit the monoamine oxidase and active the 5-HT2A (5-hydroxytryptamine) receptor, respectively, resulting in hallucinations in the users. Ayahuasca induces a psychedelic change in the anteroposterior coupling of the electrophysiological brain oscillations in humans. Traditional ayahuasca beverage is generating pharmacological, commercial and spiritual interest among the scientific community, government people, and different populations worldwide. The goal of this article is to report about the uses, chemistry and biological activities of ayahuasca. [ABSTRACT FROM AUTHOR]

Ayahuasca is a psychoactive plant mixture used in a ceremonial context throughout WesternAmazonia whose use has expanded globally in recent decades becoming popular among westerners whotravel to the Peruvian Amazon in increasing numbers to experience its reportedly healing andtransformative effects. The experience often involves participating in a shamanic dieta, which involvesfasting and ingesting non-psychoactive plants as well as a variety of plants for bodily and energeticcleansing in the form of purges and ritual baths. I demonstrate that the use of plants in this mannerconstitutes a technology intricately connected with Amazonian conceptions of the body and ultimately localeco-cosmologies that enrich our understanding of human-nature relationships and thus should form part offuture research or sustainability efforts in the area. [ABSTRACT FROM AUTHOR]

Background: Research suggests that mindfulness-based interventions may improve mindfulness-related capacities (e.g., decentering, non-judging, and non-reacting) and emotion regulation. Previously, our group reported that ayahuasca could be a potential analogue of mindfulness practice. The main aim of the current study was to examine the effects of ayahuasca on emotional regulation and mindfulness-related capacities. Secondarily, we sought to explore the effects of ayahuasca on individuals with borderline personality disorder (BPD) traits.Method: This is an observational study of 45 volunteers who participated in an ayahuasca session. The volunteers completed various self-report instruments designed to measure emotional dysregulation (Difficulties in Emotion Regulation Scale (DERS)) and mindfulness traits (Five Facet Mindfulness Questionnaire (FFMQ)-Short Form and Experiences Questionnaire (EQ)) prior to and 24 h after the ayahuasca session. The volunteers were divided into two subgroups based on their score on the McLean Screening Instrument for BPD (MSI-BPD). Twelve participants were grouped into the BPD-like traits subgroup while the rest of them were included in the non-BPD-like subgroup. We performed within-subjects and between-group analyses.Results: Overall, the participants showed significant improvements on the FFMQ subscales observing, acting with awareness, non-judging, and non-reacting and also significantly improved on decentering (EQ scale) and on the DERS subscales emotional non-acceptance, emotional interference, and lack of control. The BPD-like subgroup also showed significant improvements on the DERS subscales emotional interference and lack of control but not in mindfulness capacities.Conclusions: These findings suggest a potential therapeutic effect for ayahuasca in emotion regulation and mindfulness capacities (including decentering, acceptance, awareness, and sensitivity to meditation practice). Based on these results, we believe that ayahuasca therapy could be of value in clinical populations, such as individuals with BPD, affected by emotion dysregulation. [ABSTRACT FROM AUTHOR]

Rationale: Ayahuasca is a psychotropic plant tea from South America used for religious purposes by indigenous people of the Amazon. Increasing evidence indicates that ayahuasca may have therapeutic potential in the treatment of mental health disorders and can enhance mindfulness-related capacities. Most research so far has focused on acute and sub-acute effects of ayahuasca on mental health-related parameters and less on long-term effects.Objectives: The present study aimed to assess sub-acute and long-term effects of ayahuasca on well-being and cognitive thinking style. The second objective was to assess whether sub-acute and long-term effects of ayahuasca depend on the degree of ego dissolution that was experienced after consumption of ayahuasca.Results: Ayahuasca ceremony attendants (N = 57) in the Netherlands and Colombia were assessed before, the day after, and 4 weeks following the ritual. Relative to baseline, ratings of depression and stress significantly decreased after the ayahuasca ceremony and these changes persisted for 4 weeks. Likewise, convergent thinking improved post-ayahuasca ceremony up until the 4 weeks follow-up. Satisfaction with life and several aspects of mindfulness increased the day after the ceremony, but these changes failed to reach significance 4 weeks after. Changes in affect, satisfaction with life, and mindfulness were significantly correlated to the level of ego dissolution experienced during the ayahuasca ceremony and were unrelated to previous experience with ayahuasca.Conclusion: It is concluded that ayahuasca produces sub-acute and long-term improvements in affect and cognitive thinking style in non-pathological users. These data highlight the therapeutic potential of ayahuasca in the treatment of mental health disorders, such as depression. [ABSTRACT FROM AUTHOR]

Wastewater-based epidemiology is a promising approach worldwide, and its application is currently being developed in non-advanced economies. This technology, based on known toxicokinetic data initially used to detect illicit drugs in well-managed and maintained local sewer networks, has been extended to assess other products such as pesticides, alcohol, flame retardants, nicotine, and other substances. This technology is also used in countries with non-advanced economies. The present review aims to support future wastewater-based epidemiology in such countries by providing toxicokinetic data for locally used narcotic drugs that are expected or known to be emerging in developed countries, outlining the excretion differences due to human polymorphism, and summarising the practical obstacles due to the coverage, maintenance efficiency, or type of local sewage network.Case study feedback from Martinique is presented as an example; the Martinique field study complies with the Organisation for Economic Co-operation and Development standards for health issues, but not with regard to population and urban dynamics. [ABSTRACT FROM AUTHOR]

Purpose: We present a case report about an acute intoxication episode after an oral administration of Ayahuasca and dermal exposure of Kambo for treatment of depression. The clinical features observed were hallucination, agitation, tremors of extremities, oral paresthesia, skin lesions and seizures. Diazepam was administered by the emergency service and was effective in controlling hallucination, but failed to control agitation and seizures. Methods: Patient biological fluids (urine and serum) and the samples of Ayahuasca and Kambo were submitted to toxicological analysis using liquid-liquid extraction followed by liquid chromatography-tandem mass spectrometry and high-resolution electrospray ionization-mass spectrometry. Results: The main active compounds present in Ayahuasca, N,N-dimethyltryptamine, harmine, harmaline and tetrahydroharmine were found and quantified in the different samples, confirming the use by the patient. In Kambo secretion used in the ritual, we were able to find sixteen potently active peptides: adenoregulin, bombesin, bombesinnona peptide, bradykinin -phe(8)-psi-CHNH-arg(9)-, caerulein, deltorphin, neurokinin B, phyllomedusin, phyllocaerulein, phyllokinin, phyllolitorin, preprotachykinin B (50-79), ranatachykinin A, sauvagine, T-kinin and urechistachykinin II. Conclusions: The patient was discharged the day after exposure without any sequel. Clinical and toxicological analysis indicated that the symptoms presented by the patient occurred due to a joint action produced by the substances identified in both materials. To the best of our knowledge, this is the first case involving probable intoxication by simultaneous administration of Ayahuasca and Kambo. [ABSTRACT FROM AUTHOR]

Background: Ayahuasca is a hallucinogenic plant preparation which usually contains the vine Banisteriopsis caapi and the shrub Psychotria viridis. This tea originates from the Amazon Basin where it is used in religious ceremonies. Because interest in these religious groups spreading as well as awareness of use of ayahuasca for therapeutic and recreational purposes, its use is increasing. Banisteriopsis caapi is rich in β-carbolines, especially harmine, tetrahydroharmine and harmaline, which have monoamine oxidase inhibiting (MAOI) activity. Psychotria viridis contains the 5HT2A/2C/1A receptor agonist hallucinogen N,N-dimethyltryptamine (DMT). Usual desired effects include hallucination, dissociation, mood alteration and perception change. Undesired findings previously reported are nausea, vomiting, hypertension, and tachycardia. Methods: All human exposure calls reported to the American Association of Poison Controls Centers' (AAPCC) National Poison Data System (NPDS) between September 1, 2005 and September 1, 2015 were reviewed. Cases were filtered for specific plant derived ayahuasca-related product codes. Abstracted data included the following: case age and gender, exposure reason, exposure route, clinical manifestations, treatments given, medical outcomes and fatality. Results: Five hundred and thirty-eight exposures to ayahuasca botanical products were reported. The majority of the calls to poison control centers came from healthcare facilities (83%). The most common route of exposure was ingestion. Most cases were men (437, 81%, 95% CI 77.7% - 84.3%). The median age was 21 (IQR 18-29). Most exposures were acute. Three hundred thirty-seven (63%) were reported to have a major or moderate clinical effect. The most common clinical manifestations reported were hallucinations (35%), tachycardia (34%), agitation (34%), hypertension (16%), mydriasis (13%) and vomiting (6%). Benzodiazepines were commonly given (30%). There were 28 cases in the series who required endotracheal intubation (5%). Four cases were reported to have had a cardiac arrest and 7 a respiratory arrest. Twelve cases had a seizure. Reports of exposures called to poison centers appeared to increase during this period based on annual estimates. Three fatalities were reported. Conclusions: Ayahuasca use appears to be rising in the United States based on calls to poison control centers. While most use is reported to be safe and well tolerated, with possible beneficial effects, serious and life threatening adverse manifestations are possible. Most of the exposures reported to poison control centers were young people, more likely to be men and already in a healthcare facility. Further research, which includes comprehensive drug testing, will be needed to better identify the risks and effects of ayahuasca use. [ABSTRACT FROM AUTHOR]

Introduction: Ayahuasca is a South American psychotropic plant tea traditionally used in Amazonian shamanism. The tea contains the psychedelic 5-HT receptor agonist N, N-dimethyltryptamine (DMT), plus β-carboline alkaloids with monoamine oxidase-inhibiting properties. Increasing evidence from anecdotal reports and open-label studies indicates that ayahuasca may have therapeutic effects in treatment of substance use disorders and depression. A recent study on the psychological effects of ayahuasca found that the tea reduces judgmental processing and inner reactivity, classic goals of mindfulness psychotherapy. Another psychological facet that could potentially be targeted by ayahuasca is creative divergent thinking. This mode of thinking can enhance and strengthen psychological flexibility by allowing individuals to generate new and effective cognitive, emotional, and behavioral strategies. The present study aimed to assess the potential effects of ayahuasca on creative thinking. Methods: We visited two spiritual ayahuasca workshops and invited participants to conduct creativity tests before and during the acute effects of ayahuasca. In total, 26 participants consented. Creativity tests included the 'pattern/line meanings test' (PLMT) and the 'picture concept test' (PCT), both assessing divergent thinking and the latter also assessing convergent thinking. Results: While no significant effects were found for the PLMT, ayahuasca intake significantly modified divergent and convergent thinking as measured by the PCT. While convergent thinking decreased after intake, divergent thinking increased. Conclusions: The present data indicate that ayahuasca enhances creative divergent thinking. They suggest that ayahuasca increases psychological flexibility, which may facilitate psychotherapeutic interventions and support clinical trial initiatives. [ABSTRACT FROM AUTHOR]

Background: Ayahuasca is a psychotropic plant tea used for ritual purposes by the indigenous populations of the Amazon. In the last two decades, its use has expanded worldwide. The tea contains the psychedelic 5-HT receptor agonist N, N-dimethyltryptamine (DMT), plus β-carboline alkaloids with monoamine-oxidase-inhibiting properties. Acute administration induces an introspective dream-like experience characterized by visions and autobiographic and emotional memories. Studies of long-term users have suggested its therapeutic potential, reporting that its use has helped individuals abandon the consumption of addictive drugs. Furthermore, recent open-label studies in patients with treatment-resistant depression found that a single ayahuasca dose induced a rapid antidepressant effect that was maintained weeks after administration. Here, we conducted an exploratory study of the psychological mechanisms that could underlie the beneficial effects of ayahuasca. Methods: We assessed a group of 25 individuals before and 24 h after an ayahuasca session using two instruments designed to measure mindfulness capacities: The Five Facets Mindfulness Questionnaire (FFMQ) and the Experiences Questionnaire (EQ). Results: Ayahuasca intake led to significant increases in two facets of the FFMQ indicating a reduction in judgmental processing of experiences and in inner reactivity. It also led to a significant increase in decentering ability as measured by the EQ. These changes are classic goals of conventional mindfulness training, and the scores obtained are in the range of those observed after extensive mindfulness practice. Conclusions: The present findings support the claim that ayahuasca has therapeutic potential and suggest that this potential is due to an increase in mindfulness capacities. [ABSTRACT FROM AUTHOR]

Santo Daime, a Brazilian religion organized around a potent psychoactive beverage called ayahuasca, is now being practiced across Europe and North America. Deeming ayahuasca a dangerous 'hallucinogen,' most Western governments prosecute people who participate in Santo Daime. On the contrary, members of Santo Daime (called 'daimistas') consider ayahuasca a medicinal sacrament (or 'entheogen'). Empirical studies corroborate daimistas' claim that entheogens are benign and can be beneficial when employed in controlled contexts. Following from anthropology's goal of rendering different cultural logics as mutually explicable, this article intercedes in a misunderstanding between policies of prohibition and an emergent subculture of entheogenic therapy. [ABSTRACT FROM AUTHOR]

Background: Ayahuasca, a South American psychotropic plant tea containing the psychedelic 5-HT 2A receptor agonist N, N-dimethyltryptamine, has been shown to increase regional cerebral blood flow in prefrontal brain regions after acute administration to humans. Despite interactions at this level, neuropsychological studies have not found cognitive deficits in abstinent long-term users. Objectives: Here, we wished to investigate the effects of acute ayahuasca intake on neuropsychological performance, specifically on working memory and executive function. Methods: Twenty-four ayahuasca users (11 long-term experienced users and 13 occasional users) were assessed in their habitual setting using the Stroop, Sternberg, and Tower of London tasks prior to and following ayahuasca intake. Results: Errors in the Sternberg task increased, whereas reaction times in the Stroop task decreased and accuracy was maintained for the whole sample following ayahuasca intake. Interestingly, results in the Tower of London showed significantly increased execution and resolution times and number of movements for the occasional but not the experienced users. Additionally, a correlation analysis including all subjects showed that impaired performance in the Tower of London was inversely correlated with lifetime ayahuasca use. Conclusions: Acute ayahuasca administration impaired working memory but decreased stimulus–response interference. Interestingly, detrimental effects on higher cognition were only observed in the less experienced group. Rather than leading to increased impairment, greater prior exposure to ayahuasca was associated with reduced incapacitation. Compensatory or neuromodulatory effects associated with long-term ayahuasca intake could underlie preserved executive function in experienced users. [ABSTRACT FROM AUTHOR]

Rationale: Ayahuasca is a psychoactive tea prepared from a combination of plants that contain a hallucinogenic tryptamine and monoamine oxidase inhibitors (MAOIs). Behavioral pattern monitor (BPM) experiments demonstrated that the combination of 5-methoxy- N,N-dimethyltryptamine (5-MeO-DMT) and a behaviorally inactive dose of an MAO inhibitor such as harmaline or clorgyline induces biphasic effects on locomotor activity in rats, initially reducing locomotion and then increasing activity as time progresses. Objectives: The present study investigated whether the biphasic locomotor profile induced by the combination of 5-MeO-DMT and an MAOI is a consequence of a reduction in the rate of 5-MeO-DMT metabolism. This hypothesis was tested using a deuterated derivative of 5-MeO-DMT (α,α,β,β-tetradeutero-5-MeO-DMT) that is resistant to metabolism by MAO. Results: Confirming our previous findings, 1.0 mg/kg 5-MeO-DMT (s.c.) had biphasic effects on locomotor activity in rats pretreated with a behaviorally inactive dose of the nonselective MAOI pargyline (10 mg/kg). Administration of 5-MeO-DMT alone, even at doses greater than 1.0 mg/kg, produced only reductions in locomotor activity. Although low doses of α,α,β,β-tetradeutero-5-MeO-DMT (0.3 and 1.0 mg/kg, s.c.) produced only hypoactivity in the BPM, a dose of 3.0 mg/kg induced a biphasic locomotor profile similar to that produced by the combination of 5-MeO-DMT and an MAOI. Receptor binding studies demonstrated that deuterium substitution had little effect on the affinity of 5-MeO-DMT for a wide variety of neurotransmitter binding sites. Conclusions: The finding with α,α,β,β-tetradeutero-5-MeO-DMT indicates that the hyperactivity induced by 5-MeO-DMT after MAO inhibition is a consequence of reduced metabolism of 5-MeO-DMT, leading to prolonged occupation of central serotonin receptors. These results demonstrate that deuterated tryptamines may be useful in behavioral and pharmacological studies to mimic the effects of tryptamine/MAOI combinations. [ABSTRACT FROM AUTHOR]

Rationale: Ayahuasca is an Amazonian tea containing the natural psychedelic 5-HT agonist N, N-dimethyltryptamine (DMT). It is used in ceremonial contexts for its visionary properties. The human pharmacology of ayahuasca has been well characterized following its administration in single doses. Objectives: To evaluate the human pharmacology of ayahuasca in repeated doses and assess the potential occurrence of acute tolerance or sensitization. Methods: In a double-blind, crossover, placebo-controlled clinical trial, nine experienced psychedelic drug users received PO the two following treatment combinations at least 1 week apart: (a) a lactose placebo and then, 4 h later, an ayahuasca dose; and (b) two ayahuasca doses 4 h apart. All ayahuasca doses were freeze-dried Amazonian-sourced tea encapsulated to a standardized 0.75 mg DMT/kg bodyweight. Subjective, neurophysiological, cardiovascular, autonomic, neuroendocrine, and cell immunity measures were obtained before and at regular time intervals until 12 h after first dose administration. Results: DMT plasma concentrations, scores in subjective and neurophysiological variables, and serum prolactin and cortisol were significantly higher after two consecutive doses. When effects were standardized by plasma DMT concentrations, no differences were observed for subjective, neurophysiological, autonomic, or immunological effects. However, we observed a trend to reduced systolic blood pressure and heart rate, and a significant decrease for growth hormone (GH) after the second ayahuasca dose. Conclusions: Whereas there was no clear-cut tolerance or sensitization in the psychological sphere or most physiological variables, a trend to lower cardiovascular activation was observed, together with significant tolerance to GH secretion. [ABSTRACT FROM AUTHOR]

This study focuses on the documentation of traditional plant usage among Kichwa, the indigenous people from Canton Loreto, Ecuador. The relationship between people, plants and the natural environment is demonstrated in an ethnobotanical garden at the Capacity Building Centre of the town. The construction site for the ethnobotanical garden is a 1.5 ha secondary forest. The forest was analyzed with a local key informant and 150 different useful species were found. The plant species recorded are mainly used for medicinal purposes, followed by edible plants, and finally by food sources for animals. Open-ended interviews were conducted with the aim of identifying the most commonly used plant species among the Kichwas. The results showed that Ilex guayusa ranked most popular, followed by Myroxylon balsamum, Cedrela odorata, Banisteriopsis caapi, and Urera caracasana. Focus groups were held and the most important plant applications were evaluated. The collected data illustrated that Kichwas attach great importance to medicinal and ritual plants, followed by plants used for handcraft. Edible plants rank afterwards, followed by dye plants and plants used for hunting. The above findings serve as the backbone of the design for the ethnobotanical garden. The garden acts as a tool to preserve and promote the knowledge of plants, focusing mainly on medicinal plants. The growing areas for the plant species were determined according to their importance to the Kichwas. The concept of the ethnobotanical garden conveys the holistic picture drawn from the investigation on people and plants of the Kichwas. [ABSTRACT FROM AUTHOR]

In this paper, I discuss substance-induced visions and consider their epistemic status, meaning, and modes of proper interpretation. I focus on the visions induced by ayahuasca, a powerful psychoactive plant-made brew that has had a central status and role in the indigenous tribal cultures of the upper Amazonian region. The brew is especially famous for the visions seen with it. These are often coupled with personal psychological insights, mentations concerning topics of special significance to one, intellectual (notably, philosophical and metaphysical) ideations, as well as powerful religious and spiritual sentiments. Thus, under the intoxication, people often feel that they gain significant knowledge and understanding. The present discussion takes a cognitive-phenomenological perspective coupled with a philosophical analysis of the various epistemological questions at hand. [ABSTRACT FROM AUTHOR]

The hallucinogenic tea known as ayahuasca is made from a combination of psychoactive plants that contribute the active components N, N-dimethyltryptamine (DMT) and 5-methoxy-DMT (5-MeO-DMT), as well as the monoamine oxidase (MAO) inhibitors (MAOIs) harmine and harmaline for oral activity. The present study examined the effects of 5-MeO-DMT in combination with MAOIs in rats using the behavioral pattern monitor, which enables analyses of patterns of locomotor activity and exploration. Interaction studies using the serotonin (5-HT)1A antagonist WAY-100635 (1.0 mg/kg) and the 5-HT2A antagonist MDL 11,939 (1.0 mg/kg) were also performed to assess the respective contributions of these receptors to the behavioral effects of 5-MeO-DMT in MAOI-treated animals. 5-MeO-DMT (0.01, 0.1, and 1.0 mg/kg) decreased locomotor activity and investigatory behavior. In rats pretreated with a behaviorally inactive dose of harmaline (0.1 mg/kg), 1.0 mg/kg 5-MeO-DMT had biphasic effects on locomotor activity, initially reducing locomotion and then increasing activity as time progressed. The ability of harmaline to shift 5-MeO-DMT to a biphasic locomotor pattern was shared by the selective MAOA inhibitor clorgyline, whereas the selective MAOB inhibitor (−)-deprenyl was ineffective. The late hyperactivity induced by the combination of 1.0 mg/kg 5-MeO-DMT and 0.3 mg/kg clorgyline was blocked by pretreatment with MDL 11,939. Pretreatment with WAY-100635 failed to attenuate either the early hypoactivity or the late hyperactivity. The ability of harmaline to modify the behavioral effects of 5-MeO-DMT is mediated by the inhibition of MAOA. Furthermore, 5-HT2A receptors are responsible for the late hyperactivity induced by 5-MeO-DMT in the presence of MAOA inhibitors. [ABSTRACT FROM AUTHOR]

Ayahuasca is a traditional South American psychoactive beverage and the central sacrament of Brazilian-based religious groups, with followers in Europe and the United States. The tea contains the psychedelic indole N, N-dimethyltryptamine (DMT) and β-carboline alkaloids with monoamine oxidase-inhibiting properties that render DMT orally active. DMT interacts with serotonergic neurotransmission acting as a partial agonist at 5-HT1A and 5-HT2A/2C receptor sites. Given the role played by serotonin in the regulation of the sleep/wake cycle, we investigated the effects of daytime ayahuasca consumption in sleep parameters. Subjective sleep quality, polysomnography (PSG), and spectral analysis were assessed in a group of 22 healthy male volunteers after the administration of a placebo, an ayahuasca dose equivalent to 1 mg DMT kg−1 body weight, and 20 mg d-amphetamine, a proaminergic drug, as a positive control. Results show that ayahuasca did not induce any subjectively perceived deterioration of sleep quality or PSG-measured disruptions of sleep initiation or maintenance, in contrast with d-amphetamine, which delayed sleep initiation, disrupted sleep maintenance, induced a predominance of ‘light’ vs ‘deep’ sleep and significantly impaired subjective sleep quality. PSG analysis also showed that similarly to d-amphetamine, ayahuasca inhibits rapid eye movement (REM) sleep, decreasing its duration, both in absolute values and as a percentage of total sleep time, and shows a trend increase in its onset latency. Spectral analysis showed that d-amphetamine and ayahuasca increased power in the high frequency range, mainly during stage 2. Remarkably, whereas slow-wave sleep (SWS) power in the first night cycle, an indicator of sleep pressure, was decreased by d-amphetamine, ayahuasca enhanced power in this frequency band. Results show that daytime serotonergic psychedelic drug administration leads to measurable changes in PSG and sleep power spectrum and suggest an interaction between these drugs and brain circuits modulating REM and SWS. [ABSTRACT FROM AUTHOR]

Rationale: Ayahuasca is a South American psychoactive plant tea which contains the serotonergic psychedelic N,N-dimethyltryptamine (DMT) and monoamine-oxidase inhibitors that render DMT orally active. Previous investigations with ayahuasca have highlighted a psychotropic effect profile characterized by enhanced introspective attention, with individuals reporting altered somatic perceptions and intense emotional modifications, frequently accompanied by visual imagery. Despite recent advances in the study of ayahuasca pharmacology, the neural correlates of acute ayahuasca intoxication remain largely unknown. Objectives: To investigate the effects of ayahuasca administration on regional cerebral blood flow. Methods: Fifteen male volunteers with prior experience in the use of psychedelics received a single oral dose of encapsulated freeze-dried ayahuasca equivalent to 1.0 mg DMT/kg body weight and a placebo in a randomized double-blind clinical trial. Regional cerebral blood flow was measured 100-110 min after drug administration by means of single photon emission tomography (SPECT). Results: Ayahuasca administration led to significant activation of frontal and paralimbic brain regions. Increased blood perfusion was observed bilaterally in the anterior insula, with greater intensity in the right hemisphere, and in the anterior cingulate/frontomedial cortex of the right hemisphere, areas previously implicated in somatic awareness, subjective feeling states, and emotional arousal. Additional increases were observed in the left amygdala/parahippocampal gyrus, a structure also involved in emotional arousal. Conclusions: The present results suggest that ayahuasca interacts with neural systems that are central to interoception and emotional processing and point to a modulatory role of serotonergic neurotransmission in these processes. [ABSTRACT FROM AUTHOR]

Rationale. During binocular rivalry, two incompatible images are presented to each eye and these monocular stimuli compete for perceptual dominance, with one pattern temporarily suppressed from awareness. One variant of stimulus presentation in binocular rivalry experiments is dichoptic stimulus alternation (DSA), when stimuli are applied to the eyes in rapid reversals. There is preliminary report that in contrast with healthy controls, schizophrenic patients can maintain binocular rivalry even at very high DSA rates. Objective. The study was undertaken to investigate whether binocular rivalry survives high rates of DSA induced by the South American hallucinogenic beverage ayahuasca. Methods. Ten individuals who were participating in ayahuasca ceremonials were requested to volunteer for binocular rivalry tests (DSA=0, 3.75, 7.5, 15 and 30 Hz) without and after drinking the brew. Results. Ingestion of ayahuasca increased mean dominance periods both in standard binocular rivalry conditions (no DSA) and tests with DSA. At higher DSA rates (15 and 30 Hz) the total length of dominance periods was longer on the brew. Conclusion. It is discussed that ayahuasca-induced survival of binocular rivalry at high DSA rates may be related to slow visual processing and increased mean dominance periods may result from hallucinogen-induced alteration of gamma oscillations in the visual pathways. [ABSTRACT FROM AUTHOR]

Rationale: Ayahuasca, a South American psychotropic plant tea, combines the psychedelic agent and 5-HT[sub 2A/2C] agonist N,N-dimethyltryptamine (DMT) with β-carboline alkaloids showing monoamine oxidase-inhibiting properties. Current human research with psychedelics and entactogens has explored the possibility that drugs displaying agonist activity at the 5-HT[sub 2A/2C] sites temporally disrupt inhibitory neural mechanisms thought to intervene in the normal filtering of information. Suppression of the P50 auditory evoked potential (AEP) and prepulse inhibition of startle (PPI) are considered operational measures of sensory (P50 suppression) and sensorimotor (PPI) gating. Contrary to findings in lower animals, unexpected increases in sensorimotor gating have been found in humans following the administration of the serotonergic psychedelic psilocybin and the serotonin releaser 3,4-methylenedioxymethamphetamine (MDMA). In addition, to our knowledge P50 suppression has not been assessed previously in humans following the administration of a 5-HT[sub 2A/2C] agonist. Objectives: To assess the effects of the acute administration of ayahuasca on P50 suppression and PPI in humans, in order to evaluate the drug's modulatory actions on these measures of sensory and sensorimotor gating. Methods: Eighteen healthy volunteers with prior experience of psychedelic drug use participated in a clinical trial in which placebo or ayahuasca doses (0.6 mg and 0.85 mg DMT/kg body weight) were administered according to a double-blind, cross-over balanced design. P50 and startle reflex (pulse-alone and 60 ms, 120 ms, 240 ms and 2000 ms prepulseto-pulse intervals) recordings were undertaken at 1.5 h and 2 h after drug intake, respectively. Results: Ayahuasca produced diverging effects on each of the two gating measures evaluated. Whereas significant dose-dependent reductions of P50 suppression were observed after ayahuasca, no significant effects were found on the startle response,... [ABSTRACT FROM AUTHOR]

Abstract Rationale: Ayahuasca is a South American psychoactive beverage that contains the naturally occurring psychedelic agent N,N-dimethyltryptamine (DMT). This "tea" has been used for centuries in religious and medicinal contexts in the rain forest areas of South America and is presently gaining the attention of psychedelic users in North America and Europe. Objectives: In the present study, the psychological effects and tolerability of ayahuasca were assessed. Methods: Three increasing doses of encapsulated freeze-dried ayahuasca (0.5, 0.75, and 1.0 mg DMT/kg body weight) were administered to six healthy male volunteers with prior experience in the use of this tea, in a single-blind crossover placebo-controlled clinical trial. Results: Ayahuasca produced significant dose-dependent increases in five of the six subscales of the Hallucinogen Rating Scale, in the LSD, MBG, and A scales of the Addiction Research Center Inventory, and in the "liking", "good effects" and "high" visual analogue scales... [ABSTRACT FROM AUTHOR]