This double-blind, crossover, placebo-controlled clinical study (n=18) investigated the effects of ayahuasca (42-60mg DMT/70kg) on temporal brain activity in healthy volunteers and found an absolute power decrease in all frequency bands measured with EEG, which paralleled the time course of its subjective effects.
Abstract of Topographic pharmaco-EEG mapping of the effects of Ayahuasca
“Aims: Ayahuasca is a traditional South American psychoactive beverage used in Amazonian shamanism, and in the religious ceremonies of Brazilian-based syncretic religious groups with followers in the US and several European countries. This tea contains measurable amounts of the psychotropic indole N,N-dimethyltryptamine (DMT), and beta-carboline alkaloids with MAO-inhibiting properties. In a previous report we described a profile of stimulant and psychedelic effects for ayahuasca as measured by subjective report self-assessment instruments. In the present study the cerebral bioavailability and time-course of effects of ayahuasca were assessed in humans by means of topographic quantitative-electroencephalography (q-EEG), a noninvasive method measuring drug-induced variations in brain electrical activity.
Methods: Two doses (one low and one high) of encapsulated freeze-dried ayahuasca, equivalent to 0.6 and 0.85 mg DMT kg(-1) body weight, were administered to 18 healthy volunteers with previous experience in psychedelic drug use in a double-blind crossover placebo-controlled clinical trial. Nineteen-lead recordings were undertaken from baseline to 8 h after administration. Subjective effects were measured by means of the Hallucinogen Rating Scale (HRS).
Results: Ayahuasca induced a pattern of psychoactive effects which resulted in significant dose-dependent increases in all subscales of the HRS, and in significant and dose-dependent modifications of brain electrical activity. Absolute power decreased in all frequency bands, most prominently in the theta band. Mean absolute power decreases (95% CI) at a representative lead (P3) 90 min after the high dose were -20.20+/-15.23 microV2 and -2.70+/-2.21 microV2 for total power and theta power, respectively. Relative power decreased in the delta (-1.20+/-1.31% after 120 min at P3) and theta (-3.30+/-2.59% after 120 min at P3) bands, and increased in the beta band, most prominently in the faster beta-3 (1.00+/-0.88% after 90 min at P3) and beta-4 (0.30+/-0.24% after 90 min at P3) subbands. Finally, an increase was also seen for the centroid of the total activity and its deviation. EEG modifications began as early as 15-30 min, reached a peak between 45 and 120 min and decreased thereafter to return to baseline levels at 4-6 h after administration.
Conclusions: The central effects of ayahuasca could be objectively measured by means of q-EEG, showing a time pattern which closely paralleled that of previously reported subjective effects. The modifications seen for the individual q-EEG variables were in line with those previously described for other serotonergic psychedelics and share some features with the profile of effects shown by pro-serotonergic and pro-dopaminergic drugs. The q-EEG profile supports the role of 5-HT2 and dopamine D2-receptor agonism in mediating the effects of ayahuasca on the central nervous system.”
Authors: Jordi Riba, Peter Anderer, Adelaida Morte, Gloria Urbano, Francesc Jané, Bernd Saletu & Manel J. Barbanoj
Summary of Topographic pharmaco-EEG mapping of the effects of Ayahuasca
Ayahuasca is a psychoactive beverage obtained from the Amazon woody vine Banisteriopsis caapi. Shamans and healers have used it since pre-Columbian times and, more recently, in the United States and several European countries.
Ayahuasca tea is made by infusing Banisteriopsis caapi stems with leaves of Psychotria viridis or Diplopterys cabrerana. The leaves contain b-carboline alkaloids, mainly harmine and tetrahydroharmine (THH), followed by harmaline and trace amounts of harmol.
Ayahuasca is a combination of B. caapi and P. viridis that shows agonist activity at the 5-HT2A/2C receptors in the central nervous system. The b-carbolines in the tea prevent the metabolic breakdown of DMT and enhance the levels of endogenous catecholamines and serotonin.
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https://doi.org/10.1046/j.1365-2125.2002.01609.x
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Cite this paper (APA)
Riba, J., Anderer, P., Morte, A., Urbano, G., Jané, F., Saletu, B., & Barbanoj, M. J. (2002). Topographic pharmaco‐EEG mapping of the effects of the South American psychoactive beverage ayahuasca in healthy volunteers. British journal of clinical pharmacology, 53(6), 613-628.
Study details
Compounds studied
Ayahuasca
Topics studied
Neuroscience
Study characteristics
Original
Placebo-Controlled
Double-Blind
Within-Subject
Randomized
Participants
18
Humans
Authors
Authors associated with this publication with profiles on Blossom
Jordi RibaJordi Riba (1968 - 2020†) was a pioneering ayahuasca researcher who dedicated over two decades of work to the field. His work focussed on the pharmacokinetics and pharmacodynamics of ayahuasca, including alkaloid disposition, and electroencephalography, and neuroimaging measures of acute ayahuasca effects. He also conducted several studies on centrally-acting drugs on the acute and long-term effects of psychedelics, psychostimulants, cannabinoids, sedatives, and kappa-opioid receptor agonists. His later work moved towards investigating the neural and psychological mechanisms that could underlie the beneficial effects of ayahuasca in the treatment of various psychiatric conditions.
Institutes
Institutes associated with this publication
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Compound Details
The psychedelics given at which dose and how many times
Ayahuasca 42 - 60mg | 3x
Linked Research Papers
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Human pharmacology of ayahuasca: subjective and cardiovascular effects, monoamine metabolite excretion, and pharmacokinetics
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Effects of the South American psychoactive beverage ayahuasca on regional brain electrical activity in humans: a functional neuroimaging study using low-resolution electromagnetic tomography
This re-analysis of a double-blind, placebo-controlled clinical study (n=18) investigated the effects of ayahuasca (60mg DMT/70kg) on brain electrical activity with low-resolution electromagnetic tomography. They found a decrease in the delta, alpha-2, and beta-1 frequency rhythms over the temporo-parieto-occipital junction, and a decrease in theta rhythm in the temporomedial and frontomedial cortices.