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Human psychopharmacology and dose-effects of salvinorin A, a kappa opioid agonist hallucinogen present in the plant Salvia divinorum

December 3, 2010 / Papers, Psychology, Publications, Salvia / Salvinorin A / By / , , , ,

Abstract

Salvinorin A is a potent, selective nonnitrogenous kappa opioid agonist and the known psychoactive constituent of Salvia divinorum, a member of the mint family that has been used for centuries by Mazatec shamans of Mexico for divination and spiritual healing. S. divinorum has over the last several years gained increased popularity as a recreational drug. This is a double-blind, placebo controlled study of salvinorin A in 4 psychologically and physically healthy hallucinogen-using adults. Across sessions, participants inhaled 16 ascending doses of salvinorin A and 4 intermixed placebo doses under comfortable and supportive conditions. Doses ranged from 0.375 μg/kg to 21 μg/kg. Subject-rated drug strength was assessed every 2 min for 60 min after inhalation. Orderly time- and dose-related effects were observed. Drug strength ratings peaked at 2 min (first time point) and definite subjective effects were no longer present at approximately 20 min after inhalation. Dose-related increases were observed on questionnaire measures of mystical-type experience (Mysticism Scale) and subjective effects associated with classic serotonergic (5-HT2A) hallucinogens (Hallucinogen Rating Scale). Salvinorin A did not significantly increase heart rate or blood pressure. Participant narratives indicated intense experiences characterized by disruptions in vestibular and interoceptive signals (e.g., change in spatial orientation, pressure on the body) and unusual and sometimes recurring themes across sessions such as revisiting childhood memories, cartoon-like imagery, and contact with entities. Under these prepared and supportive conditions, salvinorin A occasioned a unique profile of subjective effects having similarities to classic hallucinogens, including mystical-type effects.

Johnson, M. W., Maclean, K.A., Reissig, C. R., Prisinzano, T. E., & Griffiths, R. R. (2010). Human psychopharmacology and dose-effects of salvinorin A, a kappa opioid agonist hallucinogen present in the plant Salvia divinorum. Drug and Alcohol Dependence, 115(1-2), 150-155. http://dx.doi.org/10.1016/j.drugalcdep.2010.11.005

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Investigating the Mechanisms of Hallucinogen-Induced Visions Using 3,4-Methylenedioxyamphetamine (MDA): A Randomized Controlled Trial in Humans

December 2, 2010 / Papers, Psychology, Publications / By / , , , , ,

Abstract

Background: The mechanisms of drug-induced visions are poorly understood. Very few serotonergic hallucinogens have been studied in humans in decades, despite widespread use of these drugs and potential relevance of their mechanisms to hallucinations occurring in psychiatric and neurological disorders.

Methodology/Principal Findings: We investigated the mechanisms of hallucinogen-induced visions by measuring the visual and perceptual effects of the hallucinogenic serotonin 5-HT2AR receptor agonist and monoamine releaser, 3,4-methylenedioxyamphetamine (MDA), in a double-blind placebo-controlled study. We found that MDA increased self-report measures of mystical-type experience and other hallucinogen-like effects, including reported visual alterations. MDA produced a significant increase in closed-eye visions (CEVs), with considerable individual variation. Magnitude of CEVs after MDA was associated with lower performance on measures of contour integration and object recognition.

Conclusions/Significance: Drug-induced visions may have greater intensity in people with poor sensory or perceptual processing, suggesting common mechanisms with other hallucinatory syndromes. MDA is a potential tool to investigate mystical experiences and visual perception.

Baggott, M. J., Siegrist, J. D., Galloway, G. P., Robertson, L. C., Coyle, J. R., & Mendelson, J. E. (2010). Investigating the Mechanisms of Hallucinogen-Induced Visions Using 3,4-Methylenedioxyamphetamine (MDA): A Randomized Controlled Trial in Humans. PLoS ONE, 5(12), 1-13. http://dx.doi.org/10.1371/journal.pone.0014074
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Evolution and origins of the Mazatec hallucinogenic sage, Salvia divinorum (Lamiaceae): a molecular phylogenetic approach

December 2, 2010 / Biology & Ethnobotany, Papers, Publications, Salvia / Salvinorin A / By / , ,

Abstract

Salvia divinorum Epl. & Játiva-M. (Lamiaceae) is a potent hallucinogenic plant that is classified within Salvia subgenus Calosphace, section Dusenostachys, and hypothesized to be an interspecific hybrid. It is of ethnobotanical significance due to its employment in traditional healing ceremonies by the Mazatecs of Oaxaca, Mexico, and due to its unique pharmacology—a highly selective, non-nitrogenous, j-opioid receptor agonist. In order to test its phylogenetic position and putative hybridity, we sequenced multiple DNA regions (ITS, trnL-trnF, and psbA-trnH) of 52 species—representing the major lineages of subgenus Calosphace—and six accessions of S. divinorum. Our molecular phylogenetic results suggest that S. divinorum should not be classified within Dusenostachys and that it is not a hybrid. Additionally, we determine that the closest known relative of this psychoactive Mexican sage is S. venulosa, a rare endemic of Colombia.

Jenks, A. A., Walker, J.B., Kim, S. C. (2010). Evolution and origins of the Mazatec hallucinogenic sage, Salvia divinorum (Lamiaceae): a molecular phylogenetic approach. Journal of Plant Research, 124(5), 593-600. http://dx.doi.org/10.1007/s10265-010-0394-6
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Psychobiology of Drug-Induced Religious Experience: From the Brain 'Locus of Religion' to Cognitive Unbinding

November 13, 2010 / Ayahuasca, LSD, Mushrooms / Psilocybin, Neuroscience, Papers, Psychology, Publications / By / ,

Abstract

The recent interest in the psychopharmacological underpinnings of religious experiences has led to both the laboratory characterizations of drug-induced mystical events and psychobiological models of religious experiences rooted in evolution and fitness. Our examination of this literature suggests that these theories may be congruent only within more modern religious and cultural settings and are not generalizable to all historical beliefs, as would be expected from an evolutionarily conserved biological mechanism. The strong influence of culture on the subjective effects of drugs as well as religious thoughts argues against the concept of a common pathway in the brain uniquely responsible for these experiences. Rather, the role of personal beliefs, expectations and experiences may interject bias into the interpretation of psychoactive drug action as a reflection of biologically based religious thought. Thus, psychobiological research proposing specific brain mechanisms should consider anthropological and historical data to address alternative explanations to the “fitness” of religious thought. A psychobiological model of the religious experience based on the concept of cognitive unbinding seems to accommodate these data better than that of a specific brain locus of religion.

Nencini, P., & Grant, G. A. (2010). Psychobiology of Drug-Induced Religious Experience: From the Brain ‘Locus of Religion’ to Cognitive Unbinding. Substance Use & Misuse, 45(13), 2130–2151. http://dx.doi.org/10.3109/10826081003713803
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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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Glutamatergic Model Psychoses: Prediction Error, Learning, and Inference

September 22, 2010 / Ketamine, Neuroscience, Papers, Psychology, Psychotic Disorders, Publications / By / , , ,

Abstract

Modulating glutamatergic neurotransmission induces alterations in conscious experience that mimic the symptoms of early psychotic illness. We review studies that use intravenous administration of ketamine, focusing on interindividual variability in the profundity of the ketamine experience. We will consider this individual variability within a hypothetical model of brain and cognitive function centered upon learning and inference. Within this model, the brains, neural systems, and even single neurons specify expectations about their inputs and responding to violations of those expectations with new learning that renders future inputs more predictable. We argue that ketamine temporarily deranges this ability by perturbing both the ways in which prior expectations are specified and the ways in which expectancy violations are signaled. We suggest that the former effect is predominantly mediated by NMDA blockade and the latter by augmented and inappropriate feedforward glutamatergic signaling. We suggest that the observed interindividual variability emerges from individual differences in neural circuits that normally underpin the learning and inference processes described. The exact source for that variability is uncertain, although it is likely to arise not only from genetic variation but also from subjects’ previous experiences and prior learning. Furthermore, we argue that chronic, unlike acute, NMDA blockade alters the specification of expectancies more profoundly and permanently. Scrutinizing individual differences in the effects of acute and chronic ketamine administration in the context of the Bayesian brain model may generate new insights about the symptoms of psychosis; their underlying cognitive processes and neurocircuitry.

Corlett, P. R., Honey, G. D., Krystal, J. H., & Fletcher, P. C. (2011). Glutamatergic Model Psychoses: Prediction Error, Learning, and Inference. Neuropsychopharmacology Reviews, 36, 294–315. http://dx.doi.org/10.1038/npp.2010.163
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Abnormal visual experiences in individuals with histories of hallucinogen use: A web-based questionnaire

September 21, 2010 / LSD, Neuroscience, Papers, Publications / By / , , , ,

Abstract

Despite longstanding reports of prolonged or reoccurring perceptual changes in a subset of hallucinogen users, very little is known about Hallucinogen Persisting Perception Disorder and related visual abnormalities in hallucinogen users. We used an online questionnaire to document the symptoms and relationship to drug use of unusual visual phenomena in hallucinogen users. 16,192 individuals viewed the information sheet and 2679 were included in the study. Of these, 224 reported having unrelated diagnoses associated with unusual visual experiences and were excluded from main analyses. Most (60.6%) of the remaining 2455 participants reported having experienced drug-free visual experiences that resembled hallucinogen effects. Probability of experiencing constant or near-constant symptoms was predicted by greater past exposure to specific hallucinogens, including lysergic acid diethylamide (LSD). Although symptoms were common, few (104, or 4.2% of the sample) found them distressing or impairing enough to consider seeking treatment. Visual changes in hallucinogen users may be more common than previously suspected and are worthy of further study.

Baggott, M. J., Coyle, J. R., Erowid, E., Erowid, F., & Robertson, L. C. (2011). Abnormal visual experiences in individuals with histories of hallucinogen use: A web-based questionnaire. Drug and alcohol dependence, 114(1), 61-67. http://dx.doi.org/10.1016/j.drugalcdep.2010.09.006
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Acute, subacute and long-term subjective effects of psilocybin in healthy humans: a pooled analysis of experimental studies

September 20, 2010 / Mushrooms / Psilocybin, Papers, Psychology, Psychotic Disorders, Publications / By / , , ,

Abstract

Psilocybin and related hallucinogenic compounds are increasingly used in human research. However, due to limited information about potential subjective side effects, the controlled medical use of these compounds has remained controversial. We therefore analysed acute, short- and longterm subjective effects of psilocybin in healthy humans by pooling raw data from eight double-blind placebo-controlled experimental studies conducted between 1999 and 2008. The analysis included 110 healthy subjects who had received 1–4 oral doses of psilocybin (45–315mg/kg body weight). Although psilocybin dose-dependently induced profound changes in mood, perception, thought and self-experience, most subjects described the experience as pleasurable, enriching and non-threatening. Acute adverse drug reactions, characterized by strong dysphoria and/or anxiety/panic, occurred only in the two highest dose conditions in a relatively small proportion of subjects. All acute adverse drug reactions were successfully managed by providing interpersonal support and did not need psychopharmacological intervention. Follow-up questionnaires indicated no subsequent drug abuse, persisting perception disorders, prolonged psychosis or other long-term impairment of functioning in any of our subjects. The results suggest that the administration of moderate doses of psilocybin to healthy, high-functioning and well-prepared subjects in the context of a carefully monitored research environment is associated with an acceptable level of risk.

Studerus, E., Kometer, M., Hasler, F., & Vollenweider, F. X. (2010). Acute, subacute and long-term subjective effects of psilocybin in healthy humans: a pooled analysis of experimental studies. Journal of Psychopharmacology, 25(11), 1434-1452. http://dx.doi.org/10.1177/0269881110382466
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The neurobiology of psychedelic drugs: implications for the treatment of mood disorders

September 10, 2010 / Depressive Disorders, DMT, Ketamine, LSD, Mescaline / Cacti, Mushrooms / Psilocybin, Papers, Psychology, Publications / By / ,

Abstract

After a pause of nearly 40 years in research into the effects of psychedelic drugs, recent advances in our understanding of the neurobiology of psychedelics, such as lysergic acid diethylamide (LSD), psilocybin and ketamine have led to renewed interest in the clinical potential of psychedelics in the treatment of various psychiatric disorders. Recent behavioural and neuroimaging data show that psychedelics modulate neural circuits that have been implicated in mood and affective disorders, and can reduce the clinical symptoms of these disorders. These findings raise the possibility that research into psychedelics might identify novel therapeutic mechanisms and approaches that are based on glutamate-driven neuroplasticity.

Vollenweider, F. X., & Kometer, M. (2010). The neurobiology of psychedelic drugs: implications for the treatment of mood disorders. Nature Reviews Neuroscience, 11, 642-651. http://dx.doi.org/10.1038/nrn2884
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Dimethyltryptamine (DMT): Subjective effects and patterns of use among Australian recreational users

September 1, 2010 / Ayahuasca, DMT, Papers, Psychology, Publications / By / ,

Abstract

Dimethyltryptamine (DMT) is an endogenous hallucinogen with traditional use as a sacrament in the orally active preparation of ayahuasca. Although the religious use of ayahuasca has been examined extensively, very little is known about the recreational use of DMT. In this study, Australian participants (n = 121) reporting at least one lifetime use of DMT completed an online questionnaire recording patterns of use, subjective effects and attitudes towards their DMT use. Smoking DMT was by far the most common route of administration (98.3%) with a comparatively smaller proportion reporting use of ayahuasca (30.6%). The reasons for first trying DMT were out of a general interest in hallucinogenic drugs (46.6%) or curiosity about DMT’s effects (41.7%), while almost one-third (31.1%) cited possible psychotherapeutic benefits of the drug. An increase in psychospiritual insight was the most commonly reported positive effect of both smoked DMT (75.5%) and ayahuasca (46.7%), a finding that is consistent with other studies examining the ritualised use of ayahuasca in a religious context. Although previous studies of DMT use have examined ayahuasca use exclusively, the present study demonstrates the ubiquity of smoking as the most prevalent route of administration among recreational DMT users.

Cakica, V., Potkonyakb, J., & Marshalla, A. (2010). Dimethyltryptamine (DMT): Subjective effects and patterns of use among Australian recreational users. Drug and Alcohol Dependence, 111(1-2), 30-37. http://dx.doi.org/10.1016/j.drugalcdep.2010.03.015
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