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Broadband cortical desynchronization underlies the human psychedelic state

September 18, 2013 / Mushrooms / Psilocybin, Neuroscience, Papers, Publications / By / , , , , , ,

Abstract

Psychedelic drugs produce profound changes in consciousness, but the underlying neurobiological mechanisms for this remain unclear. Spontaneous and induced oscillatory activity was recorded in healthy human participants with magnetoencephalography after intravenous infusion of psilocybin—prodrug of the nonselective serotonin 2A receptor agonist and classic psychedelic psilocin. Psilocybin reduced spontaneous cortical oscillatory power from 1 to 50 Hz in posterior association cortices, and from 8 to 100 Hz in frontal association cortices. Large decreases in oscillatory power were seen in areas of the default-mode network. Independent component analysis was used to identify a number of resting-state networks, and activity in these was similarly decreased after psilocybin. Psilocybin had no effect on low-level visually induced and motor-induced gamma-band oscillations, suggesting that some basic elements of oscillatory brain activity are relatively preserved during the psychedelic experience. Dynamic causal modeling revealed that posterior cingulate cortex desynchronization can be explained by increased excitability of deep-layer pyramidal neurons, which are known to be rich in 5-HT2A receptors. These findings suggest that the subjective effects of psychedelics result from a desynchronization of ongoing oscillatory rhythms in the cortex, likely triggered by 5-HT2A receptor-mediated excitation of deep pyramidal cells.

Muthukumaraswamy, S. D., Carhart-Harris, R. L., Moran, R. J., Brookes, M. J., Williams, T. M., Errtizoe, D., … & Feilding, A. (2013). Broadband cortical desynchronization underlies the human psychedelic state. The Journal of Neuroscience, 33(38), 15171-15183. 10.1523/JNEUROSCI.2063-13.2013
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Psychedelics linked to lower mental health risks

December 6, 2021 / Psychology, Publications / By

The use of LSD, magic mushrooms, or peyote does not increase a person’s risk of developing mental health problems, according to an analysis of information from more than 130,000 randomly chosen people, including 22,000 people who had used psychedelics at least once.

Researcher Teri Krebs and clinical psychologist Pål-Ørjan Johansen, from the Norwegian University of Science and Technology’s (NTNU), cleverly used data from a US national health survey to study the association between psychedelic drug use and mental health problems.

The researchers relied on data from the 2001-2004 National Survey on Drug Use and Health, in which participants were asked about mental health treatment and symptoms of a variety of mental health conditions over the past year. The specific symptoms examined were general psychological distress, anxiety disorders, mood disorders, and psychosis.

The study showed that lifetime use of psilocybin or mescaline and past year use of LSD were associated with lower rates of serious psychological distress. Lifetime use of LSD was also significantly associated with a lower rate of outpatient mental health treatment and psychiatric medicine prescription, although the nature of these relations were not demonstrated in the Norwegians’ study.

Interestingly, the results of this study confirm the outcomes of recent clinical trials that likewise do not demonstrate lasting harmful effects from the use of psychedelics in a clinical setting. It further shows that even when used non-clinically, psychedelic substances might be able to play a role in alleviating mental health issues.

The results are published in the journal PLOS One and are freely available online.

A proposal to evaluate mechanistic efficacy of hallucinogens in addiction treatment

September 1, 2013 / Ayahuasca, DMT, Iboga / Ibogaine, LSD, Mescaline / Cacti, Mushrooms / Psilocybin, Papers, Psychology, Publications, Substance Use Disorder / By / ,

Abstract

Current treatments for addiction are frequently ineffective. Hallucinogenic therapy has been indicated as helpful for a range of substance use disorders, yet this approach remains understudied and publicly unavailable. It is nonetheless a promising treatment, which has significant, long-term beneficial effects with single doses and a profile characterized by general safety, low toxicity, and non-addictiveness. However, pharmacological interventions, such as hallucinogens, should not be offered if the same effects (e.g. psychological insights/mystical experiences) and outcomes (e.g. decreased drug use) could be achieved absent pharmacological intervention. To date, there have been no clinical comparisons of drug-induced altered states with non-drug-induced states for addiction treatment. We propose and then outline a clinical trial to address this gap in knowledge. The proposed design would evaluate abstinence outcomes in a population of prescription opioid abusers after exposure to one of three conditions: a drug-induced altered state using psilocybin, a non-drug-induced altered state via hyperventilation (Holotropic Breathwork), and an active placebo with niacin. The outcomes of such a study would reveal important differences in therapeutic potential by discriminating hallucinogen-dependent effects from those psychological effects resulting from altered states.

Burdick, B. V., & Adinoff, B. (2013). A proposal to evaluate mechanistic efficacy of hallucinogens in addiction treatment. The American Journal of Drug and Alcohol Abuse, 39(5), 291-297. http://dx.doi.org/10.3109/00952990.2013.811513
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Psychedelics and Mental Health: A Population Study

August 19, 2013 / MDMA, Mescaline / Cacti, Mushrooms / Psilocybin, Papers, Psychology, Publications / By / ,

Abstract

Background
The classical serotonergic psychedelics LSD, psilocybin, mescaline are not known to cause brain damage and are regarded as non-addictive. Clinical studies do not suggest that psychedelics cause long-term mental health problems. Psychedelics have been used in the Americas for thousands of years. Over 30 million people currently living in the US have used LSD, psilocybin, or mescaline.

Objective
To evaluate the association between the lifetime use of psychedelics and current mental health in the adult population.

Method
Data drawn from years 2001 to 2004 of the National Survey on Drug Use and Health consisted of 130,152 respondents, randomly selected to be representative of the adult population in the United States. Standardized screening measures for past year mental health included serious psychological distress (K6 scale), mental health treatment (inpatient, outpatient, medication, needed but did not receive), symptoms of eight psychiatric disorders (panic disorder, major depressive episode, mania, social phobia, general anxiety disorder, agoraphobia, posttraumatic stress disorder, and non-affective psychosis), and seven specific symptoms of non-affective psychosis. We calculated weighted odds ratios by multivariate logistic regression controlling for a range of sociodemographic variables, use of illicit drugs, risk taking behavior, and exposure to traumatic events.

Results
21,967 respondents (13.4% weighted) reported lifetime psychedelic use. There were no significant associations between lifetime use of any psychedelics, lifetime use of specific psychedelics (LSD, psilocybin, mescaline, peyote), or past year use of LSD and increased rate of any of the mental health outcomes. Rather, in several cases psychedelic use was associated with lower rate of mental health problems.

Conclusion
We did not find use of psychedelics to be an independent risk factor for mental health problems.

Krebs, T. S., & Johansen, P. Ø. (2013) Psychedelics and Mental Health: A Population Study. PLoS ONE, 8(8), 1-9. http://dx.doi.org/10.1371/journal.pone.0063972
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Phylogenetic inference and trait evolution of the psychedelic mushroom genus Psilocybe sensu lato (Agaricales)

August 6, 2013 / Biology & Ethnobotany, Mushrooms / Psilocybin, Papers, Publications / By / , , , , , ,

Abstract

The genus Psilocybe contains iconic species of fungi renowned for their hallucinogenic properties. Recently, Psilocybe also included non-hallucinogenic species that have since been shifted to the genus Deconica. Here, we reconstruct a multigene phylogeny for Psilocybe, Deconica, and other exemplars of the families Hymenogastraceae and Strophariaceae sensu stricto (s. str.), using three nuclear markers (nLSU-rRNA, 5.8S rRNA, and rpb1). Our results confirm the monophyly of Deconica within Strophariaceae s. str., as well as numerous robust infrageneric relationships. Psilocybe is also recovered as a monophyletic group in the Hymenogastraceae, in which two principal lineages are recognized, including several nested subgroups. Most sections of Psilocybe following classifications based on morphological features are not supported in these analyses. Ancestral character state reconstruction analyses suggest that basidiospore shape in frontal view and spore wall thickness, commonly used to characterize sections in Deconica and Psilocybe, are homoplastic. Chrysocystidia, sterile cells located in the hymenium, evolved on at least two occasions in the Strophariaceae s. str., including in a novel lineage of Deconica.

Ramírez-Cruz, V. Guzmán, G., Villalobos-Arámbula, A. R., Rodríguez, A.,  Matheny, P. B., Sánchez-García, M., & Guzmán-Dávalos, L. (2013). Phylogenetic inference and trait evolution of the psychedelic mushroom genusPsilocybesensu lato (Agaricales). Botany, 91, 573-591. http://dx.doi.org/10.1139/cjb-2013-0070
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Spatiotemporal Brain Dynamics of Emotional Face Processing Modulations Induced by the Serotonin 1A/2A Receptor Agonist Psilocybin

July 16, 2013 / Mushrooms / Psilocybin, Neuroscience, Papers, Psychology, Publications / By / , , , , ,

Abstract

Emotional face processing is critically modulated by the serotonergic system. For instance, emotional face processing is impaired by acute psilocybin administration, a serotonin (5-HT) 1A and 2A receptor agonist. However, the spatiotemporal brain mechanisms underlying these modulations are poorly understood. Here, we investigated the spatiotemporal brain dynamics underlying psilocybin-induced modulations during emotional face processing. Electrical neuroimaging analyses were applied to visual evoked potentials in response to emotional faces, following psilocybin and placebo administration. Our results indicate a first time period of strength (i.e., Global Field Power) modulation over the 168–189 ms poststimulus interval, induced by psilocybin. A second time period of strength modulation was identified over the 211–242 ms poststimulus interval. Source estimations over these 2 time periods further revealed decreased activity in response to both neutral and fearful faces within limbic areas, including amygdala and parahippocampal gyrus, and the right temporal cortex over the 168–189 ms interval, and reduced activity in response to happy faces within limbic and right temporo-occipital brain areas over the 211–242 ms interval. Our results indicate a selective and temporally dissociable effect of psilocybin on the neuronal correlates of emotional face processing, consistent with a modulation of the top-down control.

Bernasconi, F., Schmidt, A., Pokorny, T., Kometer, M., Seifritz, E., & Vollenweider, F. X. (2013). Spatiotemporal brain dynamics of emotional face processing modulations induced by the serotonin 1A/2A receptor agonist psilocybin. Cerebral Cortex, bht178. 10.1093/cercor/bht178
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Relationship of ketamine's antidepressant and psychotomimetic effects in unipolar depression

June 25, 2013 / Depressive Disorders, Ketamine, Papers, Psychology, Publications / By / , , , , ,

Abstract

OBJECTIVES:
Ketamine and other NMDA (N-methyl-D-aspartate) antagonists produce fast-acting antidepressant-like effects, although the underlying mechanism is unclear. Furthermore, high affinity NMDA antagonists such as ketamine are associated with psychotomimetic effects. To date the link between the antidepressant and psychotomimetic effects of ketamine has not been explored. We examined the relationship between the antidepressant and psychotomimetic effects of a single ketamine infusion in subjects diagnosed with major depressive disorder.
METHODS:
In a double-blind, cross-over, placebo-controlled, two weeks clinical trial we studied the effects of ketamine (0.54 mg/kg within 30 min) in a group of 27 hospitalized depressive patients.
RESULTS:
Higher intensity of psychotomimetic symptoms, measured using BPRS, during ketamine administration correlated with alleviation in mood ratings during the following week with maximum on day seven. Ketamine was superior to placebo in all visits (day 1, 4, and 7) assessed by MADRS with effect size (Cohen´s d) of 0.62, 0.57, and 0.44 respectively. There was no significant correlation between ketamine and nor-ketamine plasma levels and MADRS score change at any study time point.
CONCLUSION:
The substantial relationship between ketamine’s antidepressant and psychotomimetic effects was found. This relationship could be mediated by the initial steps of ketamine’s action, trough NMDA receptors, shared by both ketamine’s clinical effects.
Sos, P., Klirova, M., Novak, T., Kohutova, B., Horacek, J., & Palenicek, T. (2013). Relationship of ketamine’s antidepressant and psychotomimetic effects in unipolar depression. Neuroendocrinology Letters, 34(4), 287-293.
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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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Effects of Schedule I drug laws on neuroscience research and treatment innovation

June 12, 2013 / Ayahuasca, DMT, LSD, MDMA, Mescaline / Cacti, Mushrooms / Psilocybin, Neuroscience, Papers, Publications, Salvia / Salvinorin A / By / , ,

Abstract

Many psychoactive drugs are used recreationally, particularly by young people. This use and its perceived dangers have led to many different classes of drugs being banned under national laws and international conventions. Indeed, the possession of cannabis, 3,4‑methylenedioxy‑N‑methylamphetamine (MDMA; also known as ecstasy) and psychedelics is stringently regulated. An important and unfortunate outcome of the controls placed on these and other psychoactive drugs is that they make research into their mechanisms of action and potential therapeutic uses — for example, in depression and post‑traumatic stress disorder — difficult and in many cases almost impossible.

Nutt, D. J., King, L. A., & Nichols, D. E. (2013). Effects of Schedule I drug laws on neuroscience research and treatment innovation. Nature Reviews Neuroscience, 14, 577-585. http://dx.doi.org/10.1038/nrn3530
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Peak Experiences of Psilocybin Users and Non-Users

June 4, 2013 / Mushrooms / Psilocybin, Papers, Psychology, Publications / By / ,

Abstract

Maslow (1970) defined peak experiences as the most wonderful experiences of a person’s life, which may include a sense of awe, well-being, or transcendence. Furthermore, recent research has suggested that psilocybin can produce experiences subjectively rated as uniquely meaningful and significant (Griffiths et al. 2006). It is therefore possible that psilocybin may facilitate or change the nature of peak experiences in users compared to non-users. This study was designed to compare the peak experiences of psilocybin users and non-users, to evaluate the frequency of peak experiences while under the influence of psilocybin, and to assess the perceived degree of alteration of consciousness during these experiences. Participants were recruited through convenience and snowball sampling from undergraduate classes and at a musical event. Participants were divided into three groups, those who reported a peak experience while under the influence of psilocybin (psilocybin peak experience: PPE), participants who had used psilocybin but reported their peak experiences did not occur while they were under the influence of psilocybin (non-psilocybin peak experience: NPPE), and participants who had never used psilocybin (non-user: NU). A total of 101 participants were asked to think about their peak experiences and complete a measure evaluating the degree of alteration of consciousness during that experience. Results indicated that 47% of psilocybin users reported their peak experience occurred while using psilocybin. In addition, there were significant differences among the three groups on all dimensions of alteration of consciousness. Future research is necessary to identify factors that influence the peak experiences of psilocybin users in naturalistic settings and contribute to the different characteristics of peak experiences of psilocybin users and non-users.

Cummins, C., & Lyke, J. (2013). Peak Experiences of Psilocybin Users and Non-Users. Journal of psychoactive drugs, 45(2), 189-194. 10.1080/02791072.2013.785855
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