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J. Bouso

The current state of research on ayahuasca: A systematic review of human studies assessing psychiatric symptoms, neuropsychological functioning, and neuroimaging

June 10, 2016 / Ayahuasca, Papers, Psychology, Publications, Substance Use Disorder / By / , , ,

Abstract

RATIONALE: In recent decades, the use of ayahuasca (AYA) – a β-carboline- and dimethyltryptamine-rich hallucinogenic botanical preparation traditionally used by Northwestern Amazonian tribes for ritual and therapeutic purposes – has spread from South America to Europe and the USA, raising concerns about its possible toxicity and hopes of its therapeutic potential. Thus, it is important to analyze the acute, subacute, and long-term effects of AYA to assess its safety and toxicity.

OBJECTIVES: The purpose of this study was to conduct a systematic review of human studies assessing AYA effects on psychiatric symptoms, neuropsychological functioning, and neuroimaging.

METHODS: Papers published until 16 December 2015 were included from PubMed, LILACS and SciELO databases following a comprehensive search strategy and pre-determined set of criteria for article selection.

RESULTS: The review included 28 full-text articles. Acute AYA administration was well tolerated, increased introspection and positive mood, altered visual perceptions, activated frontal and paralimbic regions and decreased default mode network activity. It also improved planning and inhibitory control and impaired working memory, and showed antidepressive and antiaddictive potentials. Long-term AYA use was associated with increased cortical thickness of the anterior cingulate cortex and cortical thinning of the posterior cingulate cortex, which was inversely correlated to age of onset, intensity of prior AYA use, and spirituality. Subacute and long-term AYA use was not associated with increased psychopathology or cognitive deficits, being associated with enhanced mood and cognition, increased spirituality, and reduced impulsivity.

CONCLUSIONS: Acute, subacute, and long-term AYA use seems to have low toxicity. Preliminary studies about potential therapeutic effects of AYA need replication due to their methodological limitations.

dos Santos, R. G., Balthazar, F. M., Bouso, J. C., & Hallak, J. E. (2016). The current state of research on ayahuasca: A systematic review of human studies assessing psychiatric symptoms, neuropsychological functioning, and neuroimaging. Journal of Psychopharmacology, 0269881116652578.

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Long-term use of psychedelic drugs is associated with differences in brain structure and personality in humans

January 16, 2015 / Ayahuasca, Neuroscience, Papers, Psychology, Publications / By / , , , , , ,

Abstract

Psychedelic agents have a long history of use by humans for their capacity to induce profound modifications in perception, emotion and cognitive processes. Despite increasing knowledge of the neural mechanisms involved in the acute effects of these drugs, the impact of sustained psychedelic use on the human brain remains largely unknown. Molecular pharmacology studies have shown that psychedelic 5-hydroxytryptamine (5HT)2A agonists stimulate neurotrophic and transcription factors associated with synaptic plasticity. These data suggest that psychedelics could potentially induce structural changes in brain tissue. Here we looked for differences in cortical thickness (CT) in regular users of psychedelics. We obtained magnetic resonance imaging (MRI) images of the brains of 22 regular users of ayahuasca (a preparation whose active principle is the psychedelic 5HT2A agonist N,N-dimethyltryptamine (DMT)) and 22 controls matched for age, sex, years of education, verbal IQ and fluid IQ. Ayahuasca users showed significant CT differences in midline structures of the brain, with thinning in the posterior cingulate cortex (PCC), a key node of the default mode network. CT values in the PCC were inversely correlated with the intensity and duration of prior use of ayahuasca and with scores on self-transcendence, a personality trait measuring religiousness, transpersonal feelings and spirituality. Although direct causation cannot be established, these data suggest that regular use of psychedelic drugs could potentially lead to structural changes in brain areas supporting attentional processes, self-referential thought, and internal mentation. These changes could underlie the previously reported personality changes in long-term users and highlight the involvement of the PCC in the effects of psychedelics.

Bouso, J. C., Palhano-Fontes, F., Rodríguez-Fornells, A., Ribeiro, S., Sanches, R., Crippa, J. A. S., … & Riba, J. (2015). Long-term use of psychedelic drugs Is associated with differences in brain structure and personality in humans. European Neuropsychopharmacology. http://dx.doi.org/10.1016/j.euroneuro.2015.01.008
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Acute effects of ayahuasca on neuropsychological performance: differences in executive function between experienced and occasional users.

June 21, 2013 / Ayahuasca, Neuroscience, Papers, Psychology, Publications / By / , , , ,

Abstract

BACKGROUND:
Ayahuasca, a South American psychotropic plant tea containing the psychedelic 5-HT2A 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.

Bouso, J. C., Fábregas, J. M., Antonijoan, R. M., Rodríguez-Fornells, A., & Riba, J. (2013). Acute effects of ayahuasca on neuropsychological performance: differences in executive function between experienced and occasional users. Psychopharmacology, 230(3), 415-424. http://dx.doi.org/10.1007/s00213-013-3167-9
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Personality, Psychopathology, Life Attitudes and Neuropsychological Performance among Ritual Users of Ayahuasca: A Longitudinal Study

August 8, 2012 / Ayahuasca, Neuroscience, Papers, Psychology, Publications / By / , , , , , ,

Abstract

Ayahuasca is an Amazonian psychoactive plant beverage containing the serotonergic 5-HT2A agonist N,N-dimethyltryptamine (DMT) and monoamine oxidase-inhibiting alkaloids (harmine, harmaline and tetrahydroharmine) that render it orally active. Ayahuasca ingestion is a central feature in several Brazilian syncretic churches that have expanded their activities to urban Brazil, Europe and North America. Members of these groups typically ingest ayahuasca at least twice per month. Prior research has shown that acute ayahuasca increases blood flow in prefrontal and temporal brain regions and that it elicits intense modifications in thought processes, perception and emotion. However, regular ayahuasca use does not seem to induce the pattern of addiction-related problems that characterize drugs of abuse. To study the impact of repeated ayahuasca use on general psychological well-being, mental health and cognition, here we assessed personality, psychopathology, life attitudes and neuropsychological performance in regular ayahuasca users (n = 127) and controls (n = 115) at baseline and 1 year later. Controls were actively participating in non-ayahuasca religions. Users showed higher Reward Dependence and Self-Transcendence and lower Harm Avoidance and Self-Directedness. They scored significantly lower on all psychopathology measures, showed better performance on the Stroop test, the Wisconsin Card Sorting Test and the Letter-Number Sequencing task from the WAIS-III, and better scores on the Frontal Systems Behavior Scale. Analysis of life attitudes showed higher scores on the Spiritual Orientation Inventory, the Purpose in Life Test and the Psychosocial Well-Being test. Despite the lower number of participants available at follow-up, overall differences with controls were maintained one year later. In conclusion, we found no evidence of psychological maladjustment, mental health deterioration or cognitive impairment in the ayahuasca-using group.

Bouso, J. C, González, D., Fondevila, S., Cutchet, M., Fernández, X., Barbosa, P. C. R., … Riba, J. (2012). Personality, Psychopathology, Life Attitudes and Neuropsychological Performance among Ritual Users of Ayahuasca: A Longitudinal Study. PLoS ONE 7(8), 1-13.  http://dx.doi.org/10.1371/journal.pone.0042421
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Metabolism and disposition of N,N-dimethyltryptamine and harmala alkaloids after oral administration of ayahuasca

April 19, 2012 / Ayahuasca, DMT, Papers, Pharmacology & Chemistry, Publications / By / , , , ,

Abstract

Ayahuasca is an Amazonian psychotropic plant tea obtained from Banisteriopsis caapi, which contains β-carboline alkaloids, chiefly harmine, harmaline and tetrahydroharmine. The tea usually incorporates the leaves of Psychotria viridis or Diplopterys cabrerana, which are rich in N,N-dimethyltryptamine (DMT), a psychedelic 5-HT2A/1A/2C agonist. The β-carbolines reversibly inhibit monoamine-oxidase (MAO), effectively preventing oxidative deamination of the orally labile DMT and allowing its absorption and access to the central nervous system. Despite increased use of the tea worldwide, the metabolism and excretion of DMT and the β-carbolines has not been studied systematically in humans following ingestion of ayahuasca. In the present work, we used an analytical method involving high performance liquid chromatography (HPLC)/electrospray ionization (ESI)/selected reaction monitoring (SRM)/tandem mass spectrometry(MS/MS) to characterize the metabolism and disposition of ayahuasca alkaloids in humans. Twenty-four-hour urine samples were obtained from 10 healthy male volunteers following administration of an oral dose of encapsulated freeze-dried ayahuasca (1.0 mg DMT/kg body weight). Results showed that less than 1% of the administered DMT dose was excreted unchanged. Around 50% was recovered as indole-3-acetic acid but also as DMT-N-oxide (10%) and other MAO-independent compounds. Recovery of DMT plus metabolites reached 68%. Harmol, harmalol, and tetrahydroharmol conjugates were abundant in urine. However, recoveries of each harmala alkaloid plus its O-demethylated metabolite varied greatly between 9 and 65%. The present results show the existence in humans of alternative metabolic routes for DMT other than biotransformation by MAO. Also that O-demethylation plus conjugation is an important but probably not the only metabolic route for the harmala alkaloids in humans.

Riba, J., McIlhenny, E. H., Valle, M., Bouso, J. C., & Barker, S. A. (2012). Metabolism and disposition of N, N‐dimethyltryptamine and harmala alkaloids after oral administration of ayahuasca. Drug testing and analysis, 4(7-8), 610-616. 10.1002/dta.1344
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MDMA-Assisted Psychotherapy Using Low Doses in a Small Sample of Women with Chronic Posttraumatic Stress Disorder

September 8, 2011 / Anxiety Disorders / PTSD, MDMA, Papers, Psychology, Publications / By / , , , ,

Abstract

The purpose of this study was to investigate the safety of different doses of MDMA-assisted psychotherapy administered in a psychotherapeutic setting to women with chronic PTSD secondary to a sexual assault, and also to obtain preliminary data regarding efficacy. Although this study was originally planned to include 29 subjects, political pressures led to the closing of the study before it could be finished, at which time only six subjects had been treated. Preliminary results from those six subjects are presented here. We found that low doses of MDMA (between 50 and 75 mg) were both psychologically and physiologically safe for all the subjects. Future studies in larger samples and using larger doses are needed in order to further clarify the safety and efficacy of MDMA in the clinical setting in subjects with PTSD.

Bouso, J. C., Doblin, R., Farré, M., Alcázar, M. Á., & Gómez-Jarabo, G. (2008). MDMA-assisted psychotherapy using low doses in a small sample of women with chronic posttraumatic stress disorder. Journal of psychoactive drugs, 40(3), 225-236., 10.1080/02791072.2008.10400637
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Assessment of addiction severity among ritual users of ayahuasca

October 1, 2010 / Ayahuasca, Papers, Psychology, Publications, Substance Use Disorder / By / , , , , , , ,

Abstract

Ayahuasca is a psychoactive beverage used for magico-religious purposes in the Amazon. Recently, Brazilian syncretic churches have helped spread the ritual use of ayahuasca abroad. This trend has raised concerns that regular use of this N,N-dimethyltryptamine-containing tea may lead to the medical and psychosocial problems typically associated with drugs of abuse. Here we assess potential drug abuse-related problems in regular ayahuasca users. Addiction severity was assessed using the Addiction Severity Index (ASI), and history of alcohol and illicit drug use was recorded. In Study 1, jungle-based ayahuasca users (n=56) were compared vs. rural controls (n=56). In Study 2, urban-based ayahuasca users (n=71) were compared vs. urban controls (n=59). Follow-up studies were conducted 1 year later. In both studies, ayahuasca users showed significantly lower scores than controls on the ASI Alcohol Use, and Psychiatric Status subscales. The jungle-based ayahuasca users showed a significantly higher frequency of previous illicit drug use but this had ceased at the time of examination, except for cannabis. At follow-up, abstinence from illicit drug use was maintained in both groups except for cannabis in Study 1. However, differences on ASI scores were still significant in the jungle-based group but not in the urban group. Despite continuing ayahuasca use, a time-dependent worsening was only observed in one subscale (Family/Social relationships) in Study 2. Overall, the ritual use of ayahuasca, as assessed with the ASI in currently active users, does not appear to be associated with the deleterious psychosocial effects typically caused by other drugs of abuse.

Fábregas, J. M., González, D., Fondevila, S., Cutchet, M., Fernández, X., Barbosa, P. C., Riba, J., … Bouso J. C. (2010). Assessment of addiction severity among ritual users of ayahuasca. Drug and Alcohol Dependence,  111(3), 257–261. http://dx.doi.org/10.1016/j.drugalcdep.2010.03.024
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