Navegando por Autor "Crippa, José Alexandre S."
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Artigo Antidepressant Effects of a Single Dose of Ayahuasca in Patients With Recurrent Depression: A SPECT Study(2016) Sanches, Rafael Faria; Osório, Flávia de Lima; Santos, Rafael G. dos; Macedo, Ligia R.H.; Maia-de-Oliveira, João Paulo; Wichert-Ana, Lauro; Araújo, Dráulio Barros de; Riba, Jordi; Crippa, José Alexandre S.; Hallak, Jaime E.C.Ayahuasca is an Amazonian botanical hallucinogenic brew which contains dimethyltryptamine, a 5-HT2A receptor agonist, and harmine, a monoamine-oxidase A inhibitor. Our group recently reported that ayahuasca administration was associated with fast-acting antidepressive effects in 6 depressive patients. The objective of the present work was to assess the antidepressive potentials of ayahuasca in a bigger sample and to investigate its effects on regional cerebral blood flow. In an open-label trial conducted in an inpatient psychiatric unit, 17 patients with recurrent depression received an oral dose of ayahuasca (2.2 mL/kg) and were evaluated with the Hamilton Rating Scale for Depression, the Montgomery-Åsberg Depression Rating Scale, the Brief Psychiatric Rating Scale, the Young Mania Rating Scale, and the Clinician Administered Dissociative States Scale during acute ayahuasca effects and 1, 7, 14, and 21 days after drug intake. Blood perfusion was assessed eight hours after drug administration by means of single photon emission tomography. Ayahuasca administration was associated with increased psychoactivity (Clinician Administered Dissociative States Scale) and significant score decreases in depression-related scales (Hamilton Rating Scale for Depression, Montgomery-Åsberg Depression Rating Scale, Brief Psychiatric Rating Scale) from 80 minutes to day 21. Increased blood perfusion in the left nucleus accumbens, right insula and left subgenual area, brain regions implicated in the regulation of mood and emotions, were observed after ayahuasca intake. Ayahuasca was well tolerated. Vomiting was the only adverse effect recorded, being reported by 47% of the volunteers. Our results suggest that ayahuasca may have fast-acting and sustained antidepressive properties. These results should be replicated in randomized, double-blind, placebo-controlled trials.Artigo Assessing the psychedelic "after-glow" in ayahuasca users: post-acute neurometabolic and functional connectivity changes are associated with enhanced mindfulness capacities(2017-06-13) Sampedro, Frederic; de la Fuente Revenga, Mario; Valle, Marta; Roberto, Natalia; Domínguez-Clavé, Elisabet; Elices, Matilde; Luna, Luís Eduardo; Crippa, José Alexandre S.; Hallak, Jaime E. C.; Araújo, Dráulio Barros de; Friedlander, Pablo; Barker, Steven A.; Álvarez, Enrique; Soler, Joaquim; Pascual, Juan C.; Feilding, Amanda; Riba, JordiBACKGROUND: Ayahuasca is a plant tea containing the psychedelic 5-HT2A agonist N,N-dimethyltryptamine (DMT) and harmala monoamine-oxidase inhibitors. Acute administration leads to neurophysiological modifications in brain regions of the default mode network (DMN), purportedly through a glutamatergic mechanism. Post-acutely, ayahuasca potentiates mindfulness capacities in volunteers, and induces rapid and sustained antidepressant effects in treatment-resistant patients. However, the mechanisms underlying these fast and maintained effects are poorly understood. Here we investigated in an open-label uncontrolled study in sixteen healthy volunteers ayahuasca-induced post-acute neurometabolic and connectivity modifications, and their association with mindfulness measures. METHODS: Using 1H-magnetic resonance spectroscopy (MRS) and functional connectivity, we compared baseline and post-acute neurometabolites and seed-to-voxel connectivity in the posterior (PCC) and anterior (ACC) cingulate cortex after a single ayahuasca dose. RESULTS: MRS showed post-acute reductions in Glx (glutamate+glutamine), creatine and NAA-NAAG (N-acetylaspartate+N-acetylaspartylglutamate) in the PCC. Connectivity was increased between the PCC and the ACC, and between the ACC and limbic structures in the right medial temporal lobe (MTL). Glx reductions correlated with increases in the "Non-Judging" subscale of the Five Facets Mindfulness Questionnaire. Increased ACC-MTL connectivity correlated with increased scores on the Self-Compassion questionnaire. Post-acute neural changes predicted sustained elevations in "Non-Judging" two months later. CONCLUSIONS: These results support the involvement of glutamate neurotransmission in the effects of psychedelics in humans. They further suggest that neurometabolic changes in the PCC, a key region within the DMN, and increased connectivity between the ACC and MTL structures involved in emotion and memory, potentially underlie the post-acute psychological effects of ayahuasca.Artigo Long-term use of psychedelic drugs is associated with differences in brain structure and personality in humans(2015) Bouso, José Carlos; Palhano-Fontes, Fernanda; Rodríguez-Fornells, Antoni; Ribeiro, Sidarta Tollendal Gomes; Sanches, Rafael; Crippa, José Alexandre S.; Hallak, Jaime E.C.; Araújo, Dráulio Barros de; Riba, JordiPsychedelic 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.