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Stoliker D, Novelli L, Vollenweider FX, Egan GF, Preller KH, Razi A. Neural Mechanisms of Resting-State Networks and the Amygdala Underlying the Cognitive and Emotional Effects of Psilocybin. Biol Psychiatry 2024; 96:57-66. [PMID: 38185235 DOI: 10.1016/j.biopsych.2024.01.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 12/19/2023] [Accepted: 01/02/2024] [Indexed: 01/09/2024]
Abstract
BACKGROUND Serotonergic psychedelics, such as psilocybin, alter perceptual and cognitive systems that are functionally integrated with the amygdala. These changes can alter cognition and emotions that are hypothesized to contribute to their therapeutic utility. However, the neural mechanisms of cognitive and subcortical systems altered by psychedelics are not well understood. METHODS We used resting-state functional magnetic resonance images collected during a randomized, double-blind, placebo-controlled clinical trial of 24 healthy adults under 0.2 mg/kg psilocybin to estimate the directed (i.e., effective) changes between the amygdala and 3 large-scale resting-state networks involved in cognition. These networks are the default mode network, the salience network, and the central executive network. RESULTS We found a pattern of decreased top-down effective connectivity from these resting-state networks to the amygdala. Effective connectivity decreased within the default mode network and salience network but increased within the central executive network. These changes in effective connectivity were statistically associated with behavioral measures of altered cognition and emotion under the influence of psilocybin. CONCLUSIONS Our findings suggest that temporary amygdala signal attenuation is associated with mechanistic changes to resting-state network connectivity. These changes are significant for altered cognition and perception and suggest targets for research investigating the efficacy of psychedelic therapy for internalizing psychiatric disorders. More broadly, our study suggests the value of quantifying the brain's hierarchical organization using effective connectivity to identify important mechanisms for basic cognitive function and how they are integrated to give rise to subjective experiences.
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Affiliation(s)
- Devon Stoliker
- Turner Institute for Brain and Mental Health, Monash University, Clayton, Victoria, Australia; Monash Biomedical Imaging, Monash University, Clayton, Victoria, Australia
| | - Leonardo Novelli
- Turner Institute for Brain and Mental Health, Monash University, Clayton, Victoria, Australia; Monash Biomedical Imaging, Monash University, Clayton, Victoria, Australia
| | - Franz X Vollenweider
- Department of Psychiatry, Psychotherapy & Psychosomatics, Psychiatric University Hospital Zurich, Zurich, Switzerland
| | - Gary F Egan
- Turner Institute for Brain and Mental Health, Monash University, Clayton, Victoria, Australia; Monash Biomedical Imaging, Monash University, Clayton, Victoria, Australia
| | - Katrin H Preller
- Department of Psychiatry, Psychotherapy & Psychosomatics, Psychiatric University Hospital Zurich, Zurich, Switzerland
| | - Adeel Razi
- Turner Institute for Brain and Mental Health, Monash University, Clayton, Victoria, Australia; Monash Biomedical Imaging, Monash University, Clayton, Victoria, Australia; Wellcome Centre for Human Neuroimaging, University College London, London, United Kingdom; CIFAR Azrieli Global Scholars Program, CIFAR, Toronto, Ontario, Canada.
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2
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Whelan TP, Daly E, Puts NA, Smith P, Allison C, Baron-Cohen S, Malievskaia E, Murphy DGM, McAlonan GM. The 'PSILAUT' protocol: an experimental medicine study of autistic differences in the function of brain serotonin targets of psilocybin. BMC Psychiatry 2024; 24:319. [PMID: 38658877 PMCID: PMC11044362 DOI: 10.1186/s12888-024-05768-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Accepted: 04/15/2024] [Indexed: 04/26/2024] Open
Abstract
BACKGROUND The underlying neurobiology of the complex autism phenotype remains obscure, although accumulating evidence implicates the serotonin system and especially the 5HT2A receptor. However, previous research has largely relied upon association or correlation studies to link differences in serotonin targets to autism. To directly establish that serotonergic signalling is involved in a candidate brain function our approach is to change it and observe a shift in that function. We will use psilocybin as a pharmacological probe of the serotonin system in vivo. We will directly test the hypothesis that serotonergic targets of psilocybin - principally, but not exclusively, 5HT2A receptor pathways-function differently in autistic and non-autistic adults. METHODS The 'PSILAUT' "shiftability" study is a case-control study autistic and non-autistic adults. How neural responses 'shift' in response to low doses (2 mg and 5 mg) of psilocybin compared to placebo will be examined using multimodal techniques including functional MRI and EEG. Each participant will attend on up to three separate visits with drug or placebo administration in a double-blind and randomized order. RESULTS This study will provide the first direct evidence that the serotonin targets of psilocybin function differently in the autistic and non-autistic brain. We will also examine individual differences in serotonin system function. CONCLUSIONS This work will inform our understanding of the neurobiology of autism as well as decisions about future clinical trials of psilocybin and/or related compounds including stratification approaches. TRIAL REGISTRATION NCT05651126.
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Affiliation(s)
- Tobias P Whelan
- Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK
- COMPASS Pathfinder Ltd, London, UK
| | - Eileen Daly
- Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK
| | - Nicolaas A Puts
- Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK
- Medical Research Council Centre for Neurodevelopmental Disorders, King's College London, London, UK
| | - Paula Smith
- Autism Research Centre, Department of Psychiatry, University of Cambridge, Cambridge, UK
| | - Carrie Allison
- Autism Research Centre, Department of Psychiatry, University of Cambridge, Cambridge, UK
| | - Simon Baron-Cohen
- Autism Research Centre, Department of Psychiatry, University of Cambridge, Cambridge, UK
| | | | - Declan G M Murphy
- Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK
- Medical Research Council Centre for Neurodevelopmental Disorders, King's College London, London, UK
- NIHR-Maudsley Biomedical Research Centre at South London and Maudsley NHS Foundation Trust and the Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - Grainne M McAlonan
- Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK.
- Medical Research Council Centre for Neurodevelopmental Disorders, King's College London, London, UK.
- NIHR-Maudsley Biomedical Research Centre at South London and Maudsley NHS Foundation Trust and the Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK.
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Solaja I, Haldane K, Mason N, Weiss B, Xu X, Xu M, Nikolin S, Jayasena T, Millard M, Brett J, Bayes A, Loo CK, Martin DM. Who are you after psychedelics? A systematic review and a meta-analysis of the magnitude of long-term effects of serotonergic psychedelics on cognition/creativity, emotional processing and personality. Neurosci Biobehav Rev 2024; 158:105570. [PMID: 38311046 DOI: 10.1016/j.neubiorev.2024.105570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Revised: 01/29/2024] [Accepted: 01/31/2024] [Indexed: 02/06/2024]
Abstract
This systematic review and a meta-analysis synthesised the results from contemporary, randomized and non-randomized controlled studies to assess lasting (one week minimum) changes on cognition/creativity, emotional processing and personality from serotonergic psychedelics. PubMed, Embase and PsycInfo were searched in July 2022. Risk of bias was assessed using Rob 2.0 and ROBINS-I. Ten studies met the eligibility criteria which involved 304 participants. No statistically significant effects were found for the majority outcome measures across the three constructs. A meta-analysis of emotional recognition outcomes found an overall significant effect for faster reaction times in the active treatment groups for disgust (SMD=-0.63, 95% CI=[-1.01 to -0.25], I2 = 65%) and sadness (SMD=-0.45, 95% CI=[-0.85 to -0.06], I2 = 60%). Future research should include larger samples, better control conditions, standardized doses and longer follow-up periods to confirm these preliminary findings.
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Affiliation(s)
- Ivana Solaja
- School of Psychiatry, Faculty of Medicine, University of New South Wales, Sydney, Australia.
| | | | - Natasha Mason
- Department of Neuropsychology and Psychopharmacology, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, Netherlands
| | - Brandon Weiss
- Centre for Psychedelic Research, Division of Academic Psychiatry, Imperial College London, London, UK
| | - Xiaomin Xu
- School of Psychiatry, Faculty of Medicine, University of New South Wales, Sydney, Australia
| | - Mei Xu
- School of Psychiatry, Faculty of Medicine, University of New South Wales, Sydney, Australia
| | - Stevan Nikolin
- School of Psychiatry, Faculty of Medicine, University of New South Wales, Sydney, Australia; Black Dog Institute, Sydney, Australia
| | - Tharusha Jayasena
- School of Psychiatry, Faculty of Medicine, University of New South Wales, Sydney, Australia
| | | | | | - Adam Bayes
- School of Psychiatry, Faculty of Medicine, University of New South Wales, Sydney, Australia; Black Dog Institute, Sydney, Australia
| | - Colleen K Loo
- School of Psychiatry, Faculty of Medicine, University of New South Wales, Sydney, Australia; Black Dog Institute, Sydney, Australia
| | - Donel M Martin
- School of Psychiatry, Faculty of Medicine, University of New South Wales, Sydney, Australia; Black Dog Institute, Sydney, Australia
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4
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Schmid Y, Bershad AK. Altered States and Social Bonds: Effects of MDMA and Serotonergic Psychedelics on Social Behavior as a Mechanism Underlying Substance-Assisted Therapy. BIOLOGICAL PSYCHIATRY. COGNITIVE NEUROSCIENCE AND NEUROIMAGING 2024:S2451-9022(24)00046-6. [PMID: 38341085 DOI: 10.1016/j.bpsc.2024.02.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Revised: 01/14/2024] [Accepted: 02/04/2024] [Indexed: 02/12/2024]
Abstract
There has been renewed interest in the use of 3,4-methylenedioxy-methamphetamine (MDMA) and serotonergic psychedelics in the treatment of multiple psychiatric disorders. Many of these compounds are known to produce prosocial effects, but how these effects relate to therapeutic efficacy and the extent to which prosocial effects are unique to a particular drug class is unknown. In this article, we present a narrative overview and compare evidence for the prosocial effects of MDMA and serotonergic psychedelics to elucidate shared mechanisms that may underlie the therapeutic process. We discuss 4 categories of prosocial effects: altered self-image, responses to social reward, responses to negative social input, and social neuroplasticity. While both categories of drugs alter self-perception, MDMA may do so in a way that is less related to the experience of mystical-type states than serotonergic psychedelics. In the case of social reward, evidence supports the ability of MDMA to enhance responses and suggests that serotonergic psychedelics may also do so, but more research is needed in this area. Both drug classes consistently dampen reactivity to negative social stimuli. Finally, preclinical evidence supports the ability of both drug classes to induce social neuroplasticity, promoting adaptive rewiring of neural circuits, which may be helpful in trauma processing. While both MDMA and serotonergic psychedelics produce prosocial effects, they differ in the mechanisms through which they do this. These differences affect the types of psychosocial interventions that may work best with each compound.
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Affiliation(s)
- Yasmin Schmid
- Clinical Pharmacology and Toxicology, Department of Biomedicine and Department of Clinical Research, University Hospital Basel and University of Basel, Switzerland; Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland
| | - Anya K Bershad
- Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, Los Angeles, California.
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5
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Gumpper RH, Roth BL. Psychedelics: preclinical insights provide directions for future research. Neuropsychopharmacology 2024; 49:119-127. [PMID: 36932180 PMCID: PMC10700551 DOI: 10.1038/s41386-023-01567-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Revised: 01/30/2023] [Accepted: 02/28/2023] [Indexed: 03/19/2023]
Abstract
Recently, psychedelics have emerged as promising therapeutics for numerous neuropsychiatric disorders. While their potential in the clinic has yet to be fully elucidated, understanding their molecular and biological mechanisms is imperative as these compounds are becoming widely used both in therapeutic and recreational contexts. This review examines the current understanding of basic biology, pharmacology, and structural biology in an attempt to reveal both the knowns and unknowns within the field.
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Affiliation(s)
- Ryan H Gumpper
- Department of Pharmacology, UNC School of Medicine, Chapel Hill, NC, 27514, USA
| | - Bryan L Roth
- Department of Pharmacology, UNC School of Medicine, Chapel Hill, NC, 27514, USA.
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6
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Pepe M, Hesami M, de la Cerda KA, Perreault ML, Hsiang T, Jones AMP. A journey with psychedelic mushrooms: From historical relevance to biology, cultivation, medicinal uses, biotechnology, and beyond. Biotechnol Adv 2023; 69:108247. [PMID: 37659744 DOI: 10.1016/j.biotechadv.2023.108247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 08/29/2023] [Accepted: 08/29/2023] [Indexed: 09/04/2023]
Abstract
Psychedelic mushrooms containing psilocybin and related tryptamines have long been used for ethnomycological purposes, but emerging evidence points to the potential therapeutic value of these mushrooms to address modern neurological, psychiatric health, and related disorders. As a result, psilocybin containing mushrooms represent a re-emerging frontier for mycological, biochemical, neuroscience, and pharmacology research. This work presents crucial information related to traditional use of psychedelic mushrooms, as well as research trends and knowledge gaps related to their diversity and distribution, technologies for quantification of tryptamines and other tryptophan-derived metabolites, as well as biosynthetic mechanisms for their production within mushrooms. In addition, we explore the current state of knowledge for how psilocybin and related tryptamines are metabolized in humans and their pharmacological effects, including beneficial and hazardous human health implications. Finally, we describe opportunities and challenges for investigating the production of psychedelic mushrooms and metabolic engineering approaches to alter secondary metabolite profiles using biotechnology integrated with machine learning. Ultimately, this critical review of all aspects related to psychedelic mushrooms represents a roadmap for future research efforts that will pave the way to new applications and refined protocols.
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Affiliation(s)
- Marco Pepe
- Department of Plant Agriculture, University of Guelph, Ontario N1G 2W1, Guelph, Canada
| | - Mohsen Hesami
- Department of Plant Agriculture, University of Guelph, Ontario N1G 2W1, Guelph, Canada
| | - Karla A de la Cerda
- School of Environmental Sciences, University of Guelph, Ontario N1G 2W1, Guelph, Canada
| | - Melissa L Perreault
- Departments of Biomedical Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Tom Hsiang
- School of Environmental Sciences, University of Guelph, Ontario N1G 2W1, Guelph, Canada
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7
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Schmitz GP, Roth BL. G protein-coupled receptors as targets for transformative neuropsychiatric therapeutics. Am J Physiol Cell Physiol 2023; 325:C17-C28. [PMID: 37067459 PMCID: PMC10281788 DOI: 10.1152/ajpcell.00397.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 03/28/2023] [Accepted: 04/06/2023] [Indexed: 04/18/2023]
Abstract
G protein-coupled receptors (GPCRs) constitute the largest family of druggable genes in the human genome. Even though perhaps 30% of approved medications target GPCRs, they interact with only a small number of them. Here, we consider whether there might be new opportunities for transformative therapeutics for neuropsychiatric disorders by specifically targeting both known and understudied GPCRs. Using psychedelic drugs that target serotonin receptors as an example, we show how recent insights into the structure, function, signaling, and cell biology of these receptors have led to potentially novel therapeutics. We next focus on the possibility that nonpsychedelic 5-HT2A receptor agonists might prove to be safe and rapidly acting antidepressants. Finally, we examine understudied and orphan GPCRs using the MRGPR family of receptors as an example.
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Affiliation(s)
- Gavin P Schmitz
- Department of Pharmacology, UNC Chapel Hill Medical School, Chapel Hill, North Carolina, United States
| | - Bryan L Roth
- Department of Pharmacology, UNC Chapel Hill Medical School, Chapel Hill, North Carolina, United States
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8
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Lee HJ, Tsang VW, Chai BS, Lin MC, Howard A, Uy C, Elefante JO. Psilocybin's Potential Mechanisms in the Treatment of Depression: A Systematic Review. J Psychoactive Drugs 2023:1-15. [PMID: 37385217 DOI: 10.1080/02791072.2023.2223195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Revised: 03/05/2023] [Accepted: 03/15/2023] [Indexed: 07/01/2023]
Abstract
Evidence suggests that psilocybin has therapeutic benefit for treating depression. However, there is little consensus regarding the mechanism by which psilocybin elicits antidepressant effects. This systematic review summarizes existing evidence. Ovid MEDLINE, EMBASE, psychINFO, and Web of Science were searched, for both human and animal studies, using a combination of MeSH Terms and free-text keywords in September 2021. No other mood disorders or psychiatric diagnoses were included. Original papers in English were included. The PRISMA framework was followed for the screening of papers. Two researchers screened the retrieved articles from the literature search, and a third researcher resolved any conflicts. Of 2,193 papers identified, 49 were selected for full-text review. 14 articles were included in the qualitative synthesis. Six supported psilocybin's mechanism of antidepressant action via changes to serotonin or glutamate receptor activity and three papers found an increase in synaptogenesis. Thirteen papers investigated changes in non-receptor or pathway-specific brain activity. Five papers found changes in functional connectivity or neurotransmission, most commonly in the hippocampus or prefrontal cortex. Several neuroreceptors, neurotransmitters, and brain areas are thought to be involved in psilocybin's ability to mitigate depressive symptoms. Psilocybin appears to alter cerebral blood flow to the amygdala and prefrontal cortex, but the evidence on changes in functional connectivity and specific receptor activity remains sparse. The lack of consensus between studies suggests that psilocybin's mechanism of action may involve a variety of pathways, demonstrating the need for more studies on psilocybin's mechanism of action as an antidepressant.
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Affiliation(s)
- Harrison J Lee
- Department of Psychiatry, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Vivian Wl Tsang
- Department of Psychiatry, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Brandon S Chai
- Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Michelle Cq Lin
- Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Andrew Howard
- Department of Psychiatry, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Christopher Uy
- Department of Neurology, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Julius O Elefante
- Department of Psychiatry, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
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9
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Sayalı C, Barrett FS. The costs and benefits of psychedelics on cognition and mood. Neuron 2023; 111:614-630. [PMID: 36681076 DOI: 10.1016/j.neuron.2022.12.031] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 12/14/2022] [Accepted: 12/24/2022] [Indexed: 01/21/2023]
Abstract
Anecdotal evidence has indicated that psychedelic substances may acutely enhance creative task performance, although empirical support for this claim is mixed at best. Clinical research has shown that psychedelics might have enduring effects on mood and well-being. However, there is no neurocognitive framework that ties acute changes in cognition to long-term effects in mood. In this review, we operationalize creativity within an emerging cognitive control framework and assess the current empirical evidence of the effects of psychedelics on creativity. Next, we leverage insights about the mechanisms and computations by which other psychoactive drugs act to enhance versus impair cognition, in particular to those that act on catecholamines, the neurophysiological consequences of which are relatively well understood. Finally, we use the same framework to link the suggested psychedelic-induced improvements in creativity with enduring psychedelic-induced improvements in mood.
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Affiliation(s)
- Ceyda Sayalı
- Center for Psychedelic and Consciousness Research, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21224, USA.
| | - Frederick S Barrett
- Center for Psychedelic and Consciousness Research, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21224, USA; Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21224, USA; Department of Psychological & Brain Sciences, Krieger School of Arts & Sciences, Johns Hopkins University, Baltimore, MD 21218, USA
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10
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Glazer J, Murray CH, Nusslock R, Lee R, de Wit H. Low doses of lysergic acid diethylamide (LSD) increase reward-related brain activity. Neuropsychopharmacology 2023; 48:418-426. [PMID: 36284231 PMCID: PMC9751270 DOI: 10.1038/s41386-022-01479-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2022] [Revised: 10/10/2022] [Accepted: 10/11/2022] [Indexed: 12/26/2022]
Abstract
Renewed interest in classic psychedelics as treatments for psychiatric disorders warrants a deeper understanding of their neural mechanisms. Single, high doses of psychedelic drugs have shown promise in treating depressive disorders, perhaps by reversing deficits in reward processing in the brain. In addition, there are anecdotal reports that repeated ingestion of low doses of LSD, or "microdosing", improve mood, cognition, and feelings of wellbeing. However, the effects of low doses of classic psychedelics on reward processing have not been studied. The current study examined the effects of two single, low doses of LSD compared to placebo on measures of reward processing. Eighteen healthy adults completed three sessions in which they received placebo (LSD-0), 13 μg LSD (LSD-13) and 26 μg LSD (LSD-26) in a within-subject, double-blind design. Neural activity was recorded while participants completed the electrophysiological monetary incentive delay task. Event-related potentials were measured during feedback processing (Reward-Positivity: RewP, Feedback-P3: FB-P3, and Late-Positive Potential: LPP). Compared to placebo, LSD-13 increased RewP and LPP amplitudes for reward (vs. neutral) feedback, and LSD-13 and LSD-26 increased FB-P3 amplitudes for positive (vs. negative) feedback. These effects were unassociated with most subjective measures of drug effects. Thus, single, low doses of LSD (vs. placebo) increased three reward-related ERP components reflecting increased hedonic (RewP), motivational (FB-P3), and affective processing of feedback (LPP). These results constitute the first evidence that low doses of LSD increase reward-related brain activity in humans. These findings may have important implications for the treatment of depressive disorders.
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Affiliation(s)
- James Glazer
- Department of Psychology, Northwestern University, 2029 Sheridan Road Evanston, Chicago, IL, 60208, USA
| | - Conor H Murray
- Department of Psychiatry and Behavioral Neuroscience, University of Chicago, 5841 S Maryland Ave, Chicago, IL, 60637, USA
| | - Robin Nusslock
- Department of Psychology, Northwestern University, 2029 Sheridan Road Evanston, Chicago, IL, 60208, USA
| | - Royce Lee
- Department of Psychiatry and Behavioral Neuroscience, University of Chicago, 5841 S Maryland Ave, Chicago, IL, 60637, USA
| | - Harriet de Wit
- Department of Psychiatry and Behavioral Neuroscience, University of Chicago, 5841 S Maryland Ave, Chicago, IL, 60637, USA.
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11
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The Altered States Database: Psychometric data from a systematic literature review. Sci Data 2022; 9:720. [PMID: 36418335 PMCID: PMC9684144 DOI: 10.1038/s41597-022-01822-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Accepted: 11/01/2022] [Indexed: 11/26/2022] Open
Abstract
In this paper, we present the development of the Altered States Database (ASDB), an open-science project based on a systematic literature review. The ASDB contains psychometric questionnaire data on subjective experiences of altered states of consciousness (ASC) induced by pharmacological and non-pharmacological methods. The systematic review follows the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Scientific journal articles were identified through PubMed and Web of Science. We included studies that examined ASC using the following validated questionnaires: Altered States of Consciousness Rating Scale (APZ, 5D-ASC, 11-ASC), Phenomenology of Consciousness Inventory (PCI), Hallucinogen Rating Scale (HRS), or Mystical Experience Questionnaire (MEQ30). The systematic review resulted in the inclusion of a total of 165 journal articles, whereof questionnaire data was extracted and is now available on the Open Science Framework (OSF) website (https://osf.io/8mbru) and on the ASDB website (http://alteredstatesdb.org), where questionnaire data can be easily retrieved and visualized. This data allows the calculation of comparable psychometric values of ASC experiences and of dose-response relationships of substances inducing ASC. Measurement(s) | Psychometric questionnaire data | Technology Type(s) | Systematic literature review (PRISMA) | Sample Characteristic - Organism | Human |
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12
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Felsch CL, Kuypers KPC. Don't be afraid, try to meditate- potential effects on neural activity and connectivity of psilocybin-assisted mindfulness-based intervention for social anxiety disorder: A systematic review. Neurosci Biobehav Rev 2022; 139:104724. [PMID: 35679988 DOI: 10.1016/j.neubiorev.2022.104724] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 04/04/2022] [Accepted: 06/02/2022] [Indexed: 01/05/2023]
Abstract
BACKGROUND Current first-line treatment for social anxiety disorder (SAD), one of the most prevalent anxiety disorders, is limited in its efficacy. Hence, novel treatment approaches are urgently needed. The current review suggests a combination of meditation-based interventions and the administration of a psychedelic as a future alternative treatment approach. While both separate treatments show promise in the treatment of (other) clinical conditions, their combination has not yet been investigated in the treatment of psychopathologies. AIM With a systematic literature review, we aim to identify the potential mechanisms by which combined psilocybin and mindfulness treatment could adjust anomalous neural activity underlying SAD and exert therapeutic effects. RESULTS Thirty experimental studies investigating the neural effects of meditation or psilocybin treatment in healthy and patient samples were included. Findings suggest that psilocybin-assisted meditation interventions might change cognitive processes like biased attention to threat linked to SAD by modulating connectivity of the salience network, balancing the activity and connectivity of cortical-midline structures, and increasing frontoparietal control over amygdala reactivity. CONCLUSIONS Future studies should investigate whether psilocybin-assisted mindfulness-based intervention can provide therapeutic benefits to SAD patients who are do not remit following conventional therapy.
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Affiliation(s)
- Corinna L Felsch
- Department of Neuropsychology and Psychopharmacology, Faculty of Psychology and Neuroscience, Maastricht University, PO Box 616, 6200 MD Maastricht, the Netherlands
| | - Kim P C Kuypers
- Department of Neuropsychology and Psychopharmacology, Faculty of Psychology and Neuroscience, Maastricht University, PO Box 616, 6200 MD Maastricht, the Netherlands.
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13
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Bălăeţ M. Psychedelic Cognition—The Unreached Frontier of Psychedelic Science. Front Neurosci 2022; 16:832375. [PMID: 35401088 PMCID: PMC8989050 DOI: 10.3389/fnins.2022.832375] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Accepted: 01/27/2022] [Indexed: 12/14/2022] Open
Abstract
Psychedelic compounds hold the promise of changing the face of neuroscience and psychiatry as we know it. There have been numerous proposals to use them to treat a range of neuropsychiatric conditions such as depression, anxiety, addiction and PTSD; and trials to date have delivered positive results in favor of the novel therapeutics. Further to the medical use, the wider healthy population is gaining interest in these compounds. We see a surge in personal use of psychedelic drugs for reasons not limited to spiritual enhancement, improved productivity, aiding the management of non-pathological anxiety and depression, and recreational interests. Notably, microdosing—the practice of taking subacute doses of psychedelic compounds—is on the rise. Our knowledge about the effects of psychedelic compounds, however, especially in naturalistic settings, is still fairly limited. In particular, one of the largest gaps concerns the acute effects on cognition caused by psychedelics. Studies carried out to date are riddled with limitations such as having disparate paradigms, small sample sizes, and insufficient breadth of testing on both unhealthy and healthy volunteers. Moreover, the studies are majoritarily limited to laboratory settings and do not assess the effects at multiple dosages within the same paradigm nor at various points throughout the psychedelic experience. This review aims to summarize the studies to date in relation to how psychedelics acutely affect different domains of cognition. In the pursuit of illuminating the current limitations and offering long-term, forward-thinking solutions, this review compares and contrasts findings related to how psychedelics impact memory, attention, reasoning, social cognition, and creativity.
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Marschall J, Fejer G, Lempe P, Prochazkova L, Kuchar M, Hajkova K, van Elk M. Psilocybin microdosing does not affect emotion-related symptoms and processing: A preregistered field and lab-based study. J Psychopharmacol 2022; 36:97-113. [PMID: 34915762 PMCID: PMC8801668 DOI: 10.1177/02698811211050556] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
BACKGROUND Microdoses of psychedelics (i.e. a sub-hallucinogenic dose taken every third day) can reduce symptoms of depression, anxiety and stress according to anecdotal reports and observational studies. Research with medium to high doses of psilocybin points towards potential underlying mechanisms, including the modulation of emotion and interoceptive processing. AIMS In this preregistered study, we investigated whether psilocybin microdoses alter self-reported interoceptive awareness and whether repeated microdosing over 3 weeks modulates emotion processing and reduces symptoms of anxiety and depression. METHODS We used a double-blind, placebo-controlled, within-subject crossover design. Participants completed the Multidimensional Assessment of Interoceptive Awareness Questionnaire 1½ h after self-administering their second dose (or placebo), and the emotional go/no-go task and the shortened Depression Anxiety Stress Scale 1½ h after self-administering their seventh dose. RESULTS Our confirmatory analyses revealed that psilocybin microdosing did not affect emotion processing or symptoms of anxiety and depression compared with placebo. Our exploratory analyses revealed that psilocybin microdosing did not affect self-reported interoceptive awareness, that symptoms of depression and stress were significantly reduced in the first block compared with baseline, that participants broke blind in the second block and that there was no effect of expectations. Further research in a substance-naïve population with clinical range anxiety and depressive symptoms is needed to substantiate the potential beneficial effects of microdosing.
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Affiliation(s)
- Josephine Marschall
- Department of Psychology, University of Amsterdam, Amsterdam, The Netherlands
| | - George Fejer
- Department of Psychology, University of Amsterdam, Amsterdam, The Netherlands
| | - Pascal Lempe
- Department of Psychology, University of Amsterdam, Amsterdam, The Netherlands
| | - Luisa Prochazkova
- Department of Psychology, Leiden University, Leiden, The Netherlands
| | - Martin Kuchar
- Forensic Laboratory of Biologically Active Substances, Department of Chemistry of Natural Compounds, University of Chemistry and Technology Prague, Prague, Czech Republic,Department of Experimental Neurobiology, National Institute of Mental Health, Klecany, Czech Republic
| | - Katerina Hajkova
- Forensic Laboratory of Biologically Active Substances, Department of Chemistry of Natural Compounds, University of Chemistry and Technology Prague, Prague, Czech Republic,Department of Experimental Neurobiology, National Institute of Mental Health, Klecany, Czech Republic
| | - Michiel van Elk
- Department of Psychology, University of Amsterdam, Amsterdam, The Netherlands,Michiel van Elk, Institute of Psychology, Leiden University, Wassenaarseweg 52, 2333 AK Leiden, The Netherlands.
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Ling S, Ceban F, Lui LMW, Lee Y, Teopiz KM, Rodrigues NB, Lipsitz O, Gill H, Subramaniapillai M, Mansur RB, Lin K, Ho R, Rosenblat JD, Castle D, McIntyre RS. Molecular Mechanisms of Psilocybin and Implications for the Treatment of Depression. CNS Drugs 2022; 36:17-30. [PMID: 34791625 DOI: 10.1007/s40263-021-00877-y] [Citation(s) in RCA: 40] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 10/28/2021] [Indexed: 12/27/2022]
Abstract
Therapeutic deficiencies with monoaminergic antidepressants invites the need to identify and develop novel rapid-acting antidepressants. Hitherto, ketamine and esketamine are identified as safe, well-tolerated rapid-acting antidepressants in adults with treatment-resistant depression, and also mitigate measures of suicidality. Psilocybin is a naturally occurring psychoactive alkaloid and non-selective agonist at many serotonin receptors, especially at serotonin 5-HT2A receptors, and is found in the Psilocybe genus of mushrooms. Preliminary studies with psilocybin have shown therapeutic promise across diverse populations including major depressive disorder. The pharmacodynamic mechanisms mediating the antidepressant and psychedelic effects of psilocybin are currently unknown but are thought to involve the modulation of the serotonergic system, primarily through agonism at the 5-HT2A receptors and downstream changes in gene expression. It is also established that indirect effects on dopaminergic and glutamatergic systems are contributory, as well as effects at other lower affinity targets. Along with the direct effects on neurochemical systems, psilocybin alters neural circuitry and key brain regions previously implicated in depression, including the default mode network and amygdala. The aim of this review is to synthesize the current understanding of the receptor pharmacology and neuronal mechanisms underlying the psychedelic and putative antidepressant properties of psilocybin.
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Affiliation(s)
- Susan Ling
- Mood Disorders Psychopharmacology Unit, Poul Hansen Family Centre for Depression, University Health Network, 399 Bathurst Street, MP 9-325, Toronto, ON, M5T 2S8, Canada.,Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, Canada
| | - Felicia Ceban
- Mood Disorders Psychopharmacology Unit, Poul Hansen Family Centre for Depression, University Health Network, 399 Bathurst Street, MP 9-325, Toronto, ON, M5T 2S8, Canada.,Brain and Cognition Discovery Foundation, Toronto, ON, Canada
| | - Leanna M W Lui
- Mood Disorders Psychopharmacology Unit, Poul Hansen Family Centre for Depression, University Health Network, 399 Bathurst Street, MP 9-325, Toronto, ON, M5T 2S8, Canada
| | - Yena Lee
- Mood Disorders Psychopharmacology Unit, Poul Hansen Family Centre for Depression, University Health Network, 399 Bathurst Street, MP 9-325, Toronto, ON, M5T 2S8, Canada.,Brain and Cognition Discovery Foundation, Toronto, ON, Canada
| | - Kayla M Teopiz
- Mood Disorders Psychopharmacology Unit, Poul Hansen Family Centre for Depression, University Health Network, 399 Bathurst Street, MP 9-325, Toronto, ON, M5T 2S8, Canada
| | - Nelson B Rodrigues
- Mood Disorders Psychopharmacology Unit, Poul Hansen Family Centre for Depression, University Health Network, 399 Bathurst Street, MP 9-325, Toronto, ON, M5T 2S8, Canada
| | - Orly Lipsitz
- Mood Disorders Psychopharmacology Unit, Poul Hansen Family Centre for Depression, University Health Network, 399 Bathurst Street, MP 9-325, Toronto, ON, M5T 2S8, Canada
| | - Hartej Gill
- Mood Disorders Psychopharmacology Unit, Poul Hansen Family Centre for Depression, University Health Network, 399 Bathurst Street, MP 9-325, Toronto, ON, M5T 2S8, Canada
| | - Mehala Subramaniapillai
- Mood Disorders Psychopharmacology Unit, Poul Hansen Family Centre for Depression, University Health Network, 399 Bathurst Street, MP 9-325, Toronto, ON, M5T 2S8, Canada
| | - Rodrigo B Mansur
- Mood Disorders Psychopharmacology Unit, Poul Hansen Family Centre for Depression, University Health Network, 399 Bathurst Street, MP 9-325, Toronto, ON, M5T 2S8, Canada.,Department of Psychiatry, University of Toronto, Toronto, ON, Canada
| | - Kangguang Lin
- Department of Affective Disorders, The Affiliated Brain Hospital of Guangzhou Medical University, (Guangzhou Huiai Hospital), Guangzhou Medical University, Guangzhou, China.,Laboratory of Emotion and Cognition, The Affiliated Brain Hospital of Guangzhou Medical University (Guangzhou Huiai Hospital), Guangzhou Medical University, Guangzhou, China
| | - Roger Ho
- Department of Psychological Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.,Institute for Health Innovation and Technology (iHealthtech), National University of Singapore, Singapore, Singapore
| | - Joshua D Rosenblat
- Mood Disorders Psychopharmacology Unit, Poul Hansen Family Centre for Depression, University Health Network, 399 Bathurst Street, MP 9-325, Toronto, ON, M5T 2S8, Canada.,Department of Psychiatry, University of Toronto, Toronto, ON, Canada
| | - David Castle
- Department of Psychiatry, University of Toronto, Toronto, ON, Canada.,Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Roger S McIntyre
- Mood Disorders Psychopharmacology Unit, Poul Hansen Family Centre for Depression, University Health Network, 399 Bathurst Street, MP 9-325, Toronto, ON, M5T 2S8, Canada. .,Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, Canada. .,Department of Psychiatry, University of Toronto, Toronto, ON, Canada. .,Brain and Cognition Discovery Foundation, Toronto, ON, Canada.
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Rucker JJ, Marwood L, Ajantaival RLJ, Bird C, Eriksson H, Harrison J, Lennard-Jones M, Mistry S, Saldarini F, Stansfield S, Tai SJ, Williams S, Weston N, Malievskaia E, Young AH. The effects of psilocybin on cognitive and emotional functions in healthy participants: Results from a phase 1, randomised, placebo-controlled trial involving simultaneous psilocybin administration and preparation. J Psychopharmacol 2022; 36:114-125. [PMID: 35090363 PMCID: PMC8801675 DOI: 10.1177/02698811211064720] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
BACKGROUND Psilocybin, a psychoactive serotonin receptor partial agonist, has been reported to acutely reduce clinical symptoms of depressive disorders. Psilocybin's effects on cognitive function have not been widely or systematically studied. AIM The aim of this study was to explore the safety of simultaneous administration of psilocybin to healthy participants in the largest randomised controlled trial of psilocybin to date. Primary and secondary endpoints assessed the short- and longer-term change in cognitive functioning, as assessed by a Cambridge Neuropsychological Test Automated Battery (CANTAB) Panel, and emotional processing scales. Safety was assessed via endpoints which included cognitive function, assessed by CANTAB global composite score, and treatment-emergent adverse event (TEAE) monitoring. METHODS In this phase 1, randomised, double-blind, placebo-controlled study, healthy participants (n = 89; mean age 36.1 years; 41 females, 48 males) were randomised to receive a single oral dose of 10 or 25 mg psilocybin, or placebo, administered simultaneously to up to six participants, with one-to-one psychological support - each participant having an assigned, dedicated therapist available throughout the session. RESULTS In total, 511 TEAEs were reported, with a median duration of 1.0 day; 67% of all TEAEs started and resolved on the day of administration. There were no serious TEAEs, and none led to study withdrawal. There were no clinically relevant between-group differences in CANTAB global composite score, CANTAB cognitive domain scores, or emotional processing scale scores. CONCLUSIONS These results indicate that 10 mg and 25 mg doses of psilocybin were generally well tolerated when given to up to six participants simultaneously and did not have any detrimental short- or long-term effects on cognitive functioning or emotional processing. CLINICAL TRIAL REGISTRATION EudraCT (https://www.clinicaltrialsregister.eu/) number: 2018-000978-30.
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Affiliation(s)
- James J Rucker
- Department of Psychological Medicine, Institute of Psychiatry, Psychology & Neuroscience, King’s College London, London, UK,South London and Maudsley NHS Foundation Trust, London, UK,James J Rucker MD, Department of Psychological Medicine, Institute of Psychiatry, Psychology & Neuroscience, King’s College London, 16 De Crespigny Park, London SE5 8AF, UK.
| | | | | | - Catherine Bird
- Department of Psychological Medicine, Institute of Psychiatry, Psychology & Neuroscience, King’s College London, London, UK
| | | | - John Harrison
- Department of Psychological Medicine, Institute of Psychiatry, Psychology & Neuroscience, King’s College London, London, UK,Alzheimer’s Center, AUmc, Amsterdam, The Netherlands,Metis Cognition Ltd., Kilmington Common, UK
| | | | | | | | | | - Sara J Tai
- Division of Psychology & Mental Health, The University of Manchester, Manchester, UK
| | | | - Neil Weston
- Department of Psychological Medicine, Institute of Psychiatry, Psychology & Neuroscience, King’s College London, London, UK
| | | | - Allan H Young
- Department of Psychological Medicine, Institute of Psychiatry, Psychology & Neuroscience, King’s College London, London, UK,South London and Maudsley NHS Foundation Trust, London, UK
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A Research Domain Criteria (RDoC)-Guided Dashboard to Review Psilocybin Target Domains: A Systematic Review. CNS Drugs 2022; 36:1031-1047. [PMID: 36097251 PMCID: PMC9550777 DOI: 10.1007/s40263-022-00944-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 07/17/2022] [Indexed: 11/03/2022]
Abstract
BACKGROUND Preliminary results from randomized controlled studies as well as identified molecular, cellular, and circuit targets of select psychedelics (e.g., psilocybin) suggest that their effects are transdiagnostic. In this review, we exploit the Research Domain Criteria (RDoC) transdiagnostic framework, to synthesize extant literature on psilocybin. OBJECTIVE We aimed to identify RDoC-based effects of psilocybin and vistas for future mechanistic and interventional research. METHODS A systematic search in electronic databases (i.e., PubMed, Scopus, PsycINFO, and Web of Science) performed in January and February 2021 identified English articles published between 1990 and 2020 reporting the effects of psilocybin on mental health measures. Data from included articles were retrieved and organized according to the RDoC bio-behavioral matrix and its constituent six main domains, namely: positive valence systems, negative valence systems, cognitive systems, social processes, sensorimotor systems, and arousal and regulatory systems. RESULTS The preponderance of research with psilocybin has differentially reported beneficial effects on positive valence systems, negative valence system, and social process domains. The data from the included studies support both short-term (23 assessments) and long-term (15 assessments) beneficial effects of psilocybin on the positive valence systems. While 12 of the extracted outcome measures suggest that psilocybin use is associated with increases in the "fear" construct of the negative valence systems domain, 19 findings show no significant effects on this construct, and seven parameters show lowered levels of the "sustained threat" construct in the long term. Thirty-four outcome measures revealed short-term alterations in the social systems' construct namely, "perception and understanding of self," and "social communications" as well as enhancements in "perception and understanding of others" and "affiliation and attachment". The majority of findings related to the cognitive systems' domain reported dyscognitive effects. There have been relatively few studies reporting outcomes of psilocybin on the remaining RDoC domains. Moreover, seven of the included studies suggest the transdiagnostic effects of psilocybin. The dashboard characterization of RDoC outcomes with psilocybin suggests beneficial effects in the measures of reward, threat, and arousal, as well as general social systems. CONCLUSIONS Psilocybin possesses a multi-domain effectiveness. The field would benefit from highly rigorous proof-of-mechanism research to assess the effects of psilocybin using the RDoC framework. The combined effect of psilocybin with psychosocial interventions with RDoC-based outcomes is a priority therapeutic vista.
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Effects of Ayahuasca on the Recognition of Facial Expressions of Emotions in Naive Healthy Volunteers: A Pilot, Proof-of-Concept, Randomized Controlled Trial. J Clin Psychopharmacol 2021; 41:267-274. [PMID: 33843820 DOI: 10.1097/jcp.0000000000001396] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
BACKGROUND The recognition of emotions in facial expressions (REFE) is a core aspect of social cognition. Previous studies with the serotonergic hallucinogens lysergic acid diethylamide and psilocybin showed that these drugs reduced the recognition of negative (fear) faces in healthy volunteers. This trial assessed the acute and prolonged effects of a single dose of ayahuasca on the REFE. METHODS Twenty-two healthy volunteers participated in a pilot, proof-of-concept, randomized trial. Study variables included a REFE task performed before and 4 hours after drug intake, subjective effects (self-reports/observer impressions), tolerability measures (cardiovascular measures, self-reports), and brain-derived neurotrophic factor plasma levels. The REFE task was applied again 1, 7, 14, and 21 days and 3 months after drug intake. Stability of ayahuasca alkaloids during the study was also assessed (room temperature, 18 months). FINDINGS Compared with placebo, ayahuasca did not modify the REFE. No significant effects were observed on cardiovascular measures and brain-derived neurotrophic factor levels. Volunteers reported visual effects, tranquility/relaxation, and well-being, with few reports of transient anxiety/confusion. Ayahuasca was well tolerated, producing mainly nausea, gastrointestinal discomfort, and vomiting. A significant time-dependent deterioration of alkaloids was observed, especially for dimethyltryptamine. CONCLUSIONS Absence of significant effects on the REFE task could be due to lack of effects of ayahuasca (at the doses used), alkaloid degradation, learning effects, and the high educational level of the sample. Further trials with different samples are needed to better understand the effects of ayahuasca and other serotonergic hallucinogens on the REFE. Future trials should improve methods to guarantee the stability of ayahuasca alkaloids.
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Abstract
BACKGROUND Psilocybin is the psychoactive component in Psilocybe mushrooms ('magic mushrooms'). Whether and how the quality of the psilocybin-induced experience might mediate beneficial health outcomes is currently under investigation, for example, in therapeutic applications. However, to date, no meta-analysis has investigated the dose-dependency of subjective experiences across available studies. AIM Establishing dose-response relationships of the subjective experiences induced by psilocybin in healthy study participants and a comparison of patient groups. METHOD We applied a linear meta-regression approach, based on the robust variance estimation framework, to obtain linear dose-response relationship estimates on questionnaire ratings after oral psilocybin administration. Data were obtained from the Altered States Database, which contains data extracted from MEDLINE-listed journal articles that used standardized and validated questionnaires: the Altered States of Consciousness Rating Scale, the Mystical Experience Questionnaire and the Hallucinogen Rating Scale. RESULTS Psilocybin dose positively correlated with ratings on most factors and scales, mainly those referring to perceptual alterations and positively experienced ego dissolution. Measures referring to challenging experiences exhibited small effects and were barely modulated by dose. CONCLUSION Psilocybin intensified almost all characteristics of altered states of consciousness assessed with the given questionnaires. Because subjective experiences are not only determined by dose, but also by individual and environmental factors, the results may only apply to controlled laboratory experiments and not to recreational use. This paper may serve as a general literature citation for the use of psilocybin in experimental and clinical research, to compare expected and observed subjective experiences.
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Affiliation(s)
- Tim Hirschfeld
- Psychotropic Substances Research Group, Charité Universitätsmedizin, Berlin, Germany
| | - Timo T Schmidt
- Psychotropic Substances Research Group, Charité Universitätsmedizin, Berlin, Germany
- Department of Education and Psychology, Freie Universität Berlin, Berlin, Germany
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Psychedelic drugs: neurobiology and potential for treatment of psychiatric disorders. Nat Rev Neurosci 2020; 21:611-624. [PMID: 32929261 DOI: 10.1038/s41583-020-0367-2] [Citation(s) in RCA: 197] [Impact Index Per Article: 49.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/07/2020] [Indexed: 12/13/2022]
Abstract
Renewed interest in the use of psychedelics in the treatment of psychiatric disorders warrants a better understanding of the neurobiological mechanisms underlying the effects of these substances. After a hiatus of about 50 years, state-of-the art studies have recently begun to close important knowledge gaps by elucidating the mechanisms of action of psychedelics with regard to their effects on receptor subsystems, systems-level brain activity and connectivity, and cognitive and emotional processing. In addition, functional studies have shown that changes in self-experience, emotional processing and social cognition may contribute to the potential therapeutic effects of psychedelics. These discoveries provide a scientific road map for the investigation and application of psychedelic substances in psychiatry.
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The Psilocybin-Telomere Hypothesis: An empirically falsifiable prediction concerning the beneficial neuropsychopharmacological effects of psilocybin on genetic aging. Med Hypotheses 2020; 134:109406. [DOI: 10.1016/j.mehy.2019.109406] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2019] [Revised: 09/21/2019] [Accepted: 09/24/2019] [Indexed: 02/06/2023]
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Preller KH, Vollenweider FX. Modulation of Social Cognition via Hallucinogens and "Entactogens". Front Psychiatry 2019; 10:881. [PMID: 31849730 PMCID: PMC6902301 DOI: 10.3389/fpsyt.2019.00881] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Accepted: 11/07/2019] [Indexed: 01/30/2023] Open
Abstract
Social cognition is a fundamental ability in human everyday lives. Deficits in social functioning also represent a core aspect of many psychiatric disorders. Yet, despite its significance, deficits in social cognition skills are insufficiently targeted by current treatments. Hallucinogens and entactogens have been shown to have the potential to modulate social processing. This article reviews the literature on the influence of hallucinogens and entactogens on social processing in controlled experimental studies in humans and elucidates the underlying neurobiological and neuropharmacological mechanisms. Furthermore, it identifies current knowledge gaps and derives implications for hallucinogen-assisted treatment approaches as well as the development of novel medication for trans-diagnostic impairments in social cognition.
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Affiliation(s)
- Katrin H Preller
- Neuropsychopharmacology and Brain Imaging, Department of Psychiatry, Psychotherapy, and Psychosomatics, University Hospital for Psychiatry Zurich, Zurich, Switzerland
| | - Franz X Vollenweider
- Neuropsychopharmacology and Brain Imaging, Department of Psychiatry, Psychotherapy, and Psychosomatics, University Hospital for Psychiatry Zurich, Zurich, Switzerland
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Rocha JM, Osório FL, Crippa JAS, Bouso JC, Rossi GN, Hallak JEC, Dos Santos RG. Serotonergic hallucinogens and recognition of facial emotion expressions: a systematic review of the literature. Ther Adv Psychopharmacol 2019; 9:2045125319845774. [PMID: 31065350 PMCID: PMC6487767 DOI: 10.1177/2045125319845774] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Accepted: 03/26/2019] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND Recognition of emotions in facial expressions (REFE) is a key aspect of social cognition. Anxiety and mood disorders are associated with deficits in REFE, and anxiolytics and antidepressants reverse these deficits. Recent studies have shown that serotonergic hallucinogens (i.e. ayahuasca, dimethyltryptamine, psilocybin, lysergic acid diethylamide [LSD], and mescaline) have anxiolytic and antidepressant properties, but their effects on REFE are not well understood. The purpose of the study was to conduct a systematic review analyzing the effects of serotonergic hallucinogens on REFE in humans. METHODS Studies published in the PubMed, PsycINFO, and Web of Science databases until 19 October 2018 which analyzed the effects of serotonergic hallucinogens on REFE in humans were included. RESULTS Of the 62 studies identified, 8 studies were included. Included studies involved the administration of a single or a few doses of LSD or psilocybin, and most trials were randomized and controlled with placebo. LSD and psilocybin reduced the recognition of negative emotions in most studies and modulated amygdala activity to these stimuli, which was correlated with antidepressive effects in patients. Both drugs were well tolerated. CONCLUSIONS Serotonergic hallucinogens reduced the recognition of negative emotions by modulating amygdala activity. Despite the small sample sizes, results suggest that serotonergic hallucinogens show promising beneficial effects on deficits in REFE.
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Affiliation(s)
- Juliana M Rocha
- Department of Neuroscience and Behavior, Ribeirão Preto Medical School, University of São Paulo, SP, Brazil
| | - Flávia L Osório
- Department of Neuroscience and Behavior, Ribeirão Preto Medical School, University of São Paulo, SP, Brazil, and National Institute of Science and Technology - Translational Medicine, Ribeirão Preto, SP, Brazil
| | - José Alexandre S Crippa
- Department of Neuroscience and Behavior, Ribeirão Preto Medical School, University of São Paulo, SP, Brazil, and National Institute of Science and Technology - Translational Medicine, Ribeirão Preto, SP, Brazil
| | - José Carlos Bouso
- ICEERS Foundation, International Center for Ethnobotanical Education, Research and Services, Barcelona, Spain
| | - Giordano N Rossi
- Department of Neuroscience and Behavior, Ribeirão Preto Medical School, University of São Paulo, SP, Brazil
| | - Jaime E C Hallak
- Department of Neuroscience and Behavior, Ribeirão Preto Medical School, University of São Paulo, SP, Brazil, and National Institute of Science and Technology - Translational Medicine, Ribeirão Preto, SP, Brazil
| | - Rafael G Dos Santos
- Departamento de Neurociências e Ciências do Comportamento, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Hospital das Clínicas, Terceiro Andar, Av. Bandeirantes, 3900, Ribeirão Preto, São Paulo, Brazil
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Millière R, Carhart-Harris RL, Roseman L, Trautwein FM, Berkovich-Ohana A. Psychedelics, Meditation, and Self-Consciousness. Front Psychol 2018; 9:1475. [PMID: 30245648 PMCID: PMC6137697 DOI: 10.3389/fpsyg.2018.01475] [Citation(s) in RCA: 131] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Accepted: 07/26/2018] [Indexed: 12/22/2022] Open
Abstract
In recent years, the scientific study of meditation and psychedelic drugs has seen remarkable developments. The increased focus on meditation in cognitive neuroscience has led to a cross-cultural classification of standard meditation styles validated by functional and structural neuroanatomical data. Meanwhile, the renaissance of psychedelic research has shed light on the neurophysiology of altered states of consciousness induced by classical psychedelics, such as psilocybin and LSD, whose effects are mainly mediated by agonism of serotonin receptors. Few attempts have been made at bridging these two domains of inquiry, despite intriguing evidence of overlap between the phenomenology and neurophysiology of meditation practice and psychedelic states. In particular, many contemplative traditions explicitly aim at dissolving the sense of self by eliciting altered states of consciousness through meditation, while classical psychedelics are known to produce significant disruptions of self-consciousness, a phenomenon known as drug-induced ego dissolution. In this article, we discuss available evidence regarding convergences and differences between phenomenological and neurophysiological data on meditation practice and psychedelic drug-induced states, with a particular emphasis on alterations of self-experience. While both meditation and psychedelics may disrupt self-consciousness and underlying neural processes, we emphasize that neither meditation nor psychedelic states can be conceived as simple, uniform categories. Moreover, we suggest that there are important phenomenological differences even between conscious states described as experiences of self-loss. As a result, we propose that self-consciousness may be best construed as a multidimensional construct, and that "self-loss," far from being an unequivocal phenomenon, can take several forms. Indeed, various aspects of self-consciousness, including narrative aspects linked to autobiographical memory, self-related thoughts and mental time travel, and embodied aspects rooted in multisensory processes, may be differently affected by psychedelics and meditation practices. Finally, we consider long-term outcomes of experiences of self-loss induced by meditation and psychedelics on individual traits and prosocial behavior. We call for caution regarding the problematic conflation of temporary states of self-loss with "selflessness" as a behavioral or social trait, although there is preliminary evidence that correlations between short-term experiences of self-loss and long-term trait alterations may exist.
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Affiliation(s)
- Raphaël Millière
- Faculty of Philosophy, University of Oxford, Oxford, United Kingdom
| | - Robin L. Carhart-Harris
- Psychedelic Research Group, Psychopharmacology Unit, Department of Medicine, Centre for Psychiatry, Imperial College London, London, United Kingdom
| | - Leor Roseman
- Psychedelic Research Group, Psychopharmacology Unit, Department of Medicine, Centre for Psychiatry, Imperial College London, London, United Kingdom
| | - Fynn-Mathis Trautwein
- Department of Social Neuroscience, Max-Planck-Institut für Kognitions- und Neurowissenschaften, Leipzig, Germany
| | - Aviva Berkovich-Ohana
- Faculty of Education, Edmond Safra Brain Research Center, University of Haifa, Haifa, Israel
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Grimm O, Kraehenmann R, Preller KH, Seifritz E, Vollenweider FX. Psilocybin modulates functional connectivity of the amygdala during emotional face discrimination. Eur Neuropsychopharmacol 2018; 28:691-700. [PMID: 29703645 DOI: 10.1016/j.euroneuro.2018.03.016] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Revised: 12/28/2017] [Accepted: 03/22/2018] [Indexed: 11/26/2022]
Abstract
Recent studies suggest that the antidepressant effects of the psychedelic 5-HT2A receptor agonist psilocybin are mediated through its modulatory properties on prefrontal and limbic brain regions including the amygdala. To further investigate the effects of psilocybin on emotion processing networks, we studied for the first-time psilocybin's acute effects on amygdala seed-to-voxel connectivity in an event-related face discrimination task in 18 healthy volunteers who received psilocybin and placebo in a double-blind balanced cross-over design. The amygdala has been implicated as a salience detector especially involved in the immediate response to emotional face content. We used beta-series amygdala seed-to-voxel connectivity during an emotional face discrimination task to elucidate the connectivity pattern of the amygdala over the entire brain. When we compared psilocybin to placebo, an increase in reaction time for all three categories of affective stimuli was found. Psilocybin decreased the connectivity between amygdala and the striatum during angry face discrimination. During happy face discrimination, the connectivity between the amygdala and the frontal pole was decreased. No effect was seen during discrimination of fearful faces. Thus, we show psilocybin's effect as a modulator of major connectivity hubs of the amygdala. Psilocybin decreases the connectivity between important nodes linked to emotion processing like the frontal pole or the striatum. Future studies are needed to clarify whether connectivity changes predict therapeutic effects in psychiatric patients.
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Affiliation(s)
- O Grimm
- University Hospital Frankfurt, Departement of Psychiatry, Psychosomatics and Psychotherapy, Frankfurt am Main, Germany; Psychiatric Hospital Zürich, Department of Psychiatry, Psychotherapy and Psychosomatics, Zürich, Switzerland.
| | - R Kraehenmann
- Psychiatric Hospital Zürich, Department of Psychiatry, Psychotherapy and Psychosomatics, Zürich, Switzerland
| | - K H Preller
- Psychiatric Hospital Zürich, Department of Psychiatry, Psychotherapy and Psychosomatics, Zürich, Switzerland
| | - E Seifritz
- Psychiatric Hospital Zürich, Department of Psychiatry, Psychotherapy and Psychosomatics, Zürich, Switzerland
| | - F X Vollenweider
- Psychiatric Hospital Zürich, Department of Psychiatry, Psychotherapy and Psychosomatics, Zürich, Switzerland
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Abstract
BACKGROUND A resurgence of neurobiological and clinical research is currently underway into the therapeutic potential of serotonergic or 'classical' psychedelics, such as the prototypical psychedelic drug lysergic acid diethylamide (LSD), psilocybin (4-phosphoryloxy-N,Ndimethyltryptamine), and ayahuasca - a betacarboline- and dimethyltryptamine (DMT)-containing Amazonian beverage. The aim of this review is to introduce readers to the similarities and dissimilarities between psychedelic states and night dreams, and to draw conclusions related to therapeutic applications of psychedelics in psychiatry. METHODS Research literature related to psychedelics and dreaming is reviewed, and these two states of consciousness are systematically compared. Relevant conclusions with regard to psychedelicassisted therapy will be provided. RESULTS Common features between psychedelic states and night dreams include perception, mental imagery, emotion activation, fear memory extinction, and sense of self and body. Differences between these two states are related to differential perceptual input from the environment, clarity of consciousness and meta-cognitive abilities. Therefore, psychedelic states are closest to lucid dreaming which is characterized by a mixed state of dreaming and waking consciousness. CONCLUSION The broad overlap between dreaming and psychedelic states supports the notion that psychedelics acutely induce dreamlike subjective experiences which may have long-term beneficial effects on psychosocial functioning and well-being. Future clinical studies should examine how therapeutic outcome is related to the acute dreamlike effects of psychedelics.
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Affiliation(s)
- Rainer Kraehenmann
- Neuropsychopharmacology and Brain Imaging, Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric Hospital, Faculty of Medicine, University of Zurich, Zurich. Switzerland
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Kometer M, Vollenweider FX. Serotonergic Hallucinogen-Induced Visual Perceptual Alterations. Curr Top Behav Neurosci 2018; 36:257-282. [PMID: 27900674 DOI: 10.1007/7854_2016_461] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Serotonergic hallucinogens, such as lysergic acid diethylamide (LSD), psilocybin, and N,N-dimethyltryptamine (DMT), are famous for their capacity to temporally and profoundly alter an individual's visual experiences. These visual alterations show consistent attributes despite large inter- and intra-individual variances. Many reports document a common perception of colors as more saturated, with increased brightness and contrast in the environment ("Visual Intensifications"). Environmental objects might be altered in size ("Visual illusions") or take on a modified and special meaning for the subject ("Altered self-reference"). Subjects may perceive light flashes or geometrical figures containing recurrent patterns ("Elementary imagery and hallucinations") influenced by auditory stimuli ("Audiovisual synesthesia"), or they may envision images of people, animals, or landscapes ("Complex imagery and hallucinations") without any physical stimuli supporting their percepts. This wide assortment of visual phenomena suggests that one single neuropsychopharmacological mechanism is unlikely to explain such vast phenomenological diversity. Starting with mechanisms that act at the cellular level, the key role of 5-HT2A receptor activation and the subsequent increased cortical excitation will be considered. Next, it will be shown that area specific anatomical and dynamical features link increased excitation to the specific visual contents of hallucinations. The decrease of alpha oscillations by hallucinogens will then be introduced as a systemic mechanism for amplifying internal-driven excitation that overwhelms stimulus-induced excitations. Finally, the hallucinogen-induced parallel decrease of the N170 visual evoked potential and increased medial P1 potential will be discussed as key mechanisms for inducing a dysbalance between global integration and early visual gain that may explain several hallucinogen-induced visual experiences, including visual hallucinations, illusions, and intensifications.
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Affiliation(s)
- Michael Kometer
- Neuropsychopharmacology and Brain Imaging Research Unit, Heffter Research Center Zurich, Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric University Hospital, University of Zurich, Lenggstrasse 31, 8032, Zurich, Switzerland.
| | - Franz X Vollenweider
- Neuropsychopharmacology and Brain Imaging Research Unit, Heffter Research Center Zurich, Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric University Hospital, University of Zurich, Lenggstrasse 31, 8032, Zurich, Switzerland
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28
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Interoceptive signals impact visual processing: Cardiac modulation of visual body perception. Neuroimage 2017; 158:176-185. [DOI: 10.1016/j.neuroimage.2017.06.064] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Revised: 06/19/2017] [Accepted: 06/22/2017] [Indexed: 11/19/2022] Open
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Pokorny T, Preller KH, Kometer M, Dziobek I, Vollenweider FX. Effect of Psilocybin on Empathy and Moral Decision-Making. Int J Neuropsychopharmacol 2017; 20:747-757. [PMID: 28637246 PMCID: PMC5581487 DOI: 10.1093/ijnp/pyx047] [Citation(s) in RCA: 99] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/29/2016] [Revised: 05/01/2017] [Accepted: 06/14/2017] [Indexed: 12/30/2022] Open
Abstract
Background Impaired empathic abilities lead to severe negative social consequences and influence the development and treatment of several psychiatric disorders. Furthermore, empathy has been shown to play a crucial role in moral and prosocial behavior. Although the serotonin system has been implicated in modulating empathy and moral behavior, the relative contribution of the various serotonin receptor subtypes is still unknown. Methods We investigated the acute effect of psilocybin (0.215 mg/kg p.o.) in healthy human subjects on different facets of empathy and hypothetical moral decision-making using the multifaceted empathy test (n=32) and the moral dilemma task (n=24). Results Psilocybin significantly increased emotional, but not cognitive empathy compared with placebo, and the increase in implicit emotional empathy was significantly associated with psilocybin-induced changed meaning of percepts. In contrast, moral decision-making remained unaffected by psilocybin. Conclusions These findings provide first evidence that psilocybin has distinct effects on social cognition by enhancing emotional empathy but not moral behavior. Furthermore, together with previous findings, psilocybin appears to promote emotional empathy presumably via activation of serotonin 2A/1A receptors, suggesting that targeting serotonin 2A/1A receptors has implications for potential treatment of dysfunctional social cognition.
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Affiliation(s)
- Thomas Pokorny
- Neuropsychopharmacology and Brain Imaging, Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric Hospital, University of Zurich, Zurich, Switzerland (Mr Pokorny, and Drs Preller, Kometer, and Vollenweider); Heffter Research Center Zurich, Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric Hospital, University of Zurich, Zurich, Switzerland (Mr Pokorny, and Drs Preller, Kometer, and Vollenweider); Berlin School of Mind and Brain, Humboldt-Universität zu Berlin, Berlin, Germany (Dr Dziobek)
| | - Katrin H Preller
- Neuropsychopharmacology and Brain Imaging, Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric Hospital, University of Zurich, Zurich, Switzerland (Mr Pokorny, and Drs Preller, Kometer, and Vollenweider); Heffter Research Center Zurich, Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric Hospital, University of Zurich, Zurich, Switzerland (Mr Pokorny, and Drs Preller, Kometer, and Vollenweider); Berlin School of Mind and Brain, Humboldt-Universität zu Berlin, Berlin, Germany (Dr Dziobek)
| | - Michael Kometer
- Neuropsychopharmacology and Brain Imaging, Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric Hospital, University of Zurich, Zurich, Switzerland (Mr Pokorny, and Drs Preller, Kometer, and Vollenweider); Heffter Research Center Zurich, Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric Hospital, University of Zurich, Zurich, Switzerland (Mr Pokorny, and Drs Preller, Kometer, and Vollenweider); Berlin School of Mind and Brain, Humboldt-Universität zu Berlin, Berlin, Germany (Dr Dziobek)
| | - Isabel Dziobek
- Neuropsychopharmacology and Brain Imaging, Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric Hospital, University of Zurich, Zurich, Switzerland (Mr Pokorny, and Drs Preller, Kometer, and Vollenweider); Heffter Research Center Zurich, Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric Hospital, University of Zurich, Zurich, Switzerland (Mr Pokorny, and Drs Preller, Kometer, and Vollenweider); Berlin School of Mind and Brain, Humboldt-Universität zu Berlin, Berlin, Germany (Dr Dziobek)
| | - Franz X Vollenweider
- Neuropsychopharmacology and Brain Imaging, Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric Hospital, University of Zurich, Zurich, Switzerland (Mr Pokorny, and Drs Preller, Kometer, and Vollenweider); Heffter Research Center Zurich, Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric Hospital, University of Zurich, Zurich, Switzerland (Mr Pokorny, and Drs Preller, Kometer, and Vollenweider); Berlin School of Mind and Brain, Humboldt-Universität zu Berlin, Berlin, Germany (Dr Dziobek)
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Lewis CR, Preller KH, Kraehenmann R, Michels L, Staempfli P, Vollenweider FX. Two dose investigation of the 5-HT-agonist psilocybin on relative and global cerebral blood flow. Neuroimage 2017; 159:70-78. [PMID: 28711736 DOI: 10.1016/j.neuroimage.2017.07.020] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Revised: 07/07/2017] [Accepted: 07/11/2017] [Indexed: 11/19/2022] Open
Abstract
Psilocybin, the active compound in psychedelic mushrooms, is an agonist of various serotonin receptors. Seminal psilocybin positron emission tomography (PET) research suggested regional increases in glucose metabolism in frontal cortex (hyperfrontality). However, a recent arterial spin labeling (ASL) study suggests psilocybin may lead to hypo-perfusion in various brain regions. In this placebo-controlled, double-blind study we used pseudo-continuous ASL (pCASL) to measure perfusion changes, with and without adjustment for global brain perfusion, after two doses of oral psilocybin (low dose: 0.160 mg/kg; high dose: 0.215 mg/kg) in two groups of healthy controls (n = 29 in both groups, total N = 58) during rest. We controlled for sex and age and used family-wise error corrected p values in all neuroimaging analyses. Both dose groups reported profound subjective drug effects as measured by the Altered States of Consciousness Rating Scale (5D-ASC) with the high dose inducing significantly larger effects in four out of the 11 scales. After adjusting for global brain perfusion, psilocybin increased relative perfusion in distinct right hemispheric frontal and temporal regions and bilaterally in the anterior insula and decreased perfusion in left hemispheric parietal and temporal cortices and left subcortical regions. Whereas, psilocybin significantly reduced absolute perfusion in frontal, temporal, parietal, and occipital lobes, and bilateral amygdalae, anterior cingulate, insula, striatal regions, and hippocampi. Our analyses demonstrate consistency with both the hyperfrontal hypothesis of psilocybin and the more recent study demonstrating decreased perfusion, depending on analysis method. Importantly, our data illustrate that relative changes in perfusion should be understood and interpreted in relation to absolute signal variations.
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Affiliation(s)
- Candace R Lewis
- Neuropsychopharmacology and Brain Imaging, Department of Psychiatry, Psychotherapy and Psychosomatics, University Hospital for Psychiatry Zurich, Lenggstr. 31, 8032, Zurich, Switzerland.
| | - Katrin H Preller
- Neuropsychopharmacology and Brain Imaging, Department of Psychiatry, Psychotherapy and Psychosomatics, University Hospital for Psychiatry Zurich, Lenggstr. 31, 8032, Zurich, Switzerland
| | - Rainer Kraehenmann
- Neuropsychopharmacology and Brain Imaging, Department of Psychiatry, Psychotherapy and Psychosomatics, University Hospital for Psychiatry Zurich, Lenggstr. 31, 8032, Zurich, Switzerland
| | - Lars Michels
- Institute of Neuroradiology, University Hospital Zurich, Zurich, Switzerland Center of MR-Research, University Children's Hospital Zurich, Ramistr. 100, 8091, Zurich, Switzerland
| | - Philipp Staempfli
- Neuropsychopharmacology and Brain Imaging, Department of Psychiatry, Psychotherapy and Psychosomatics, University Hospital for Psychiatry Zurich, Lenggstr. 31, 8032, Zurich, Switzerland
| | - Franz X Vollenweider
- Neuropsychopharmacology and Brain Imaging, Department of Psychiatry, Psychotherapy and Psychosomatics, University Hospital for Psychiatry Zurich, Lenggstr. 31, 8032, Zurich, Switzerland
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Hildebrandt A, Kiy A, Reuter M, Sommer W, Wilhelm O. Face and emotion expression processing and the serotonin transporter polymorphism 5-HTTLPR/rs22531. GENES BRAIN AND BEHAVIOR 2016; 15:453-64. [PMID: 27079569 DOI: 10.1111/gbb.12295] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Revised: 03/19/2016] [Accepted: 04/08/2016] [Indexed: 12/13/2022]
Abstract
Face cognition, including face identity and facial expression processing, is a crucial component of socio-emotional abilities, characterizing humans as highest developed social beings. However, for these trait domains molecular genetic studies investigating gene-behavior associations based on well-founded phenotype definitions are still rare. We examined the relationship between 5-HTTLPR/rs25531 polymorphisms - related to serotonin-reuptake - and the ability to perceive and recognize faces and emotional expressions in human faces. For this aim we conducted structural equation modeling on data from 230 young adults, obtained by using a comprehensive, multivariate task battery with maximal effort tasks. By additionally modeling fluid intelligence and immediate and delayed memory factors, we aimed to address the discriminant relationships of the 5-HTTLPR/rs25531 polymorphisms with socio-emotional abilities. We found a robust association between the 5-HTTLPR/rs25531 polymorphism and facial emotion perception. Carriers of two long (L) alleles outperformed carriers of one or two S alleles. Weaker associations were present for face identity perception and memory for emotional facial expressions. There was no association between the 5-HTTLPR/rs25531 polymorphism and non-social abilities, demonstrating discriminant validity of the relationships. We discuss the implications and possible neural mechanisms underlying these novel findings.
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Affiliation(s)
- A Hildebrandt
- Department of Psychology, Ernst-Moritz-Arndt-Universität Greifswald
| | - A Kiy
- Department of Psychology, Ernst-Moritz-Arndt-Universität Greifswald
| | - M Reuter
- Department of Psychology, Rheinische Friedrich-Wilhelms-Universität Bonn.,Center for Economics & Neuroscience (CENs), Laboratory of Neurogenetics, University of Bonn
| | - W Sommer
- Department of Psychology, Humboldt-Universität zu Berlin
| | - O Wilhelm
- Institute of Psychology and Education, Ulm University, Germany
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Effects of serotonin 2A/1A receptor stimulation on social exclusion processing. Proc Natl Acad Sci U S A 2016; 113:5119-24. [PMID: 27091970 DOI: 10.1073/pnas.1524187113] [Citation(s) in RCA: 108] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Social ties are crucial for physical and mental health. However, psychiatric patients frequently encounter social rejection. Moreover, an increased reactivity to social exclusion influences the development, progression, and treatment of various psychiatric disorders. Nevertheless, the neuromodulatory substrates of rejection experiences are largely unknown. The preferential serotonin (5-HT) 2A/1A receptor agonist, psilocybin (Psi), reduces the processing of negative stimuli, but whether 5-HT2A/1A receptor stimulation modulates the processing of negative social interactions remains unclear. Therefore, this double-blind, randomized, counterbalanced, cross-over study assessed the neural response to social exclusion after the acute administration of Psi (0.215 mg/kg) or placebo (Pla) in 21 healthy volunteers by using functional magnetic resonance imaging (fMRI) and resting-state magnetic resonance spectroscopy (MRS). Participants reported a reduced feeling of social exclusion after Psi vs. Pla administration, and the neural response to social exclusion was decreased in the dorsal anterior cingulate cortex (dACC) and the middle frontal gyrus, key regions for social pain processing. The reduced neural response in the dACC was significantly correlated with Psi-induced changes in self-processing and decreased aspartate (Asp) content. In conclusion, 5-HT2A/1A receptor stimulation with psilocybin seems to reduce social pain processing in association with changes in self-experience. These findings may be relevant to the normalization of negative social interaction processing in psychiatric disorders characterized by increased rejection sensitivity. The current results also emphasize the importance of 5-HT2A/1A receptor subtypes and the Asp system in the control of social functioning, and as prospective targets in the treatment of sociocognitive impairments in psychiatric illnesses.
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Pokorny T, Preller KH, Kraehenmann R, Vollenweider FX. Modulatory effect of the 5-HT1A agonist buspirone and the mixed non-hallucinogenic 5-HT1A/2A agonist ergotamine on psilocybin-induced psychedelic experience. Eur Neuropsychopharmacol 2016; 26:756-66. [PMID: 26875114 DOI: 10.1016/j.euroneuro.2016.01.005] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Revised: 12/08/2015] [Accepted: 01/15/2016] [Indexed: 11/18/2022]
Abstract
The mixed serotonin (5-HT) 1A/2A/2B/2C/6/7 receptor agonist psilocybin dose-dependently induces an altered state of consciousness (ASC) that is characterized by changes in sensory perception, mood, thought, and the sense of self. The psychological effects of psilocybin are primarily mediated by 5-HT2A receptor activation. However, accumulating evidence suggests that 5-HT1A or an interaction between 5-HT1A and 5-HT2A receptors may contribute to the overall effects of psilocybin. Therefore, we used a double-blind, counterbalanced, within-subject design to investigate the modulatory effects of the partial 5-HT1A agonist buspirone (20mg p.o.) and the non-hallucinogenic 5-HT2A/1A agonist ergotamine (3mg p.o.) on psilocybin-induced (170 µg/kg p.o.) psychological effects in two groups (n=19, n=17) of healthy human subjects. Psychological effects were assessed using the Altered State of Consciousness (5D-ASC) rating scale. Buspirone significantly reduced the 5D-ASC main scale score for Visionary Restructuralization (VR) (p<0.001), which was mostly driven by a reduction of the VR item cluster scores for elementary and complex visual hallucinations. Further, buspirone also reduced the main scale score for Oceanic Boundlessness (OB) including derealisation and depersonalisation phenomena at a trend level (p=0.062), whereas ergotamine did not show any effects on the psilocybin-induced 5D-ASC main scale scores. The present finding demonstrates that buspirone exerts inhibitory effects on psilocybin-induced effects, presumably via 5-HT1A receptor activation, an interaction between 5-HT1A and 5-HT2A receptors, or both. The data suggest that the modulation of 5-HT1A receptor activity may be a useful target in the treatment of visual hallucinations in different psychiatric and neurological diseases.
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Affiliation(s)
- Thomas Pokorny
- Neuropsychopharmacology and Brain Imaging, Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric Hospital, University of Zurich, Zurich, Switzerland; Heffter Research Center Zurich, Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric Hospital, University of Zurich, Zurich, Switzerland
| | - Katrin H Preller
- Neuropsychopharmacology and Brain Imaging, Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric Hospital, University of Zurich, Zurich, Switzerland; Heffter Research Center Zurich, Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric Hospital, University of Zurich, Zurich, Switzerland
| | - Rainer Kraehenmann
- Neuropsychopharmacology and Brain Imaging, Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric Hospital, University of Zurich, Zurich, Switzerland; Heffter Research Center Zurich, Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric Hospital, University of Zurich, Zurich, Switzerland
| | - Franz X Vollenweider
- Neuropsychopharmacology and Brain Imaging, Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric Hospital, University of Zurich, Zurich, Switzerland; Heffter Research Center Zurich, Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric Hospital, University of Zurich, Zurich, Switzerland.
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Abstract
Psychedelics (serotonergic hallucinogens) are powerful psychoactive substances that alter perception and mood and affect numerous cognitive processes. They are generally considered physiologically safe and do not lead to dependence or addiction. Their origin predates written history, and they were employed by early cultures in many sociocultural and ritual contexts. After the virtually contemporaneous discovery of (5R,8R)-(+)-lysergic acid-N,N-diethylamide (LSD)-25 and the identification of serotonin in the brain, early research focused intensively on the possibility that LSD and other psychedelics had a serotonergic basis for their action. Today there is a consensus that psychedelics are agonists or partial agonists at brain serotonin 5-hydroxytryptamine 2A receptors, with particular importance on those expressed on apical dendrites of neocortical pyramidal cells in layer V. Several useful rodent models have been developed over the years to help unravel the neurochemical correlates of serotonin 5-hydroxytryptamine 2A receptor activation in the brain, and a variety of imaging techniques have been employed to identify key brain areas that are directly affected by psychedelics. Recent and exciting developments in the field have occurred in clinical research, where several double-blind placebo-controlled phase 2 studies of psilocybin-assisted psychotherapy in patients with cancer-related psychosocial distress have demonstrated unprecedented positive relief of anxiety and depression. Two small pilot studies of psilocybin-assisted psychotherapy also have shown positive benefit in treating both alcohol and nicotine addiction. Recently, blood oxygen level-dependent functional magnetic resonance imaging and magnetoencephalography have been employed for in vivo brain imaging in humans after administration of a psychedelic, and results indicate that intravenously administered psilocybin and LSD produce decreases in oscillatory power in areas of the brain's default mode network.
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Affiliation(s)
- David E Nichols
- Eschelman School of Pharmacy, University of North Carolina, Chapel Hill, North Carolina
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35
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Bernasconi F, Kometer M, Pokorny T, Seifritz E, Vollenweider FX. The electrophysiological effects of the serotonin 1A receptor agonist buspirone in emotional face processing. Eur Neuropsychopharmacol 2015; 25:474-82. [PMID: 25637265 DOI: 10.1016/j.euroneuro.2015.01.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2014] [Revised: 01/06/2015] [Accepted: 01/10/2015] [Indexed: 10/24/2022]
Abstract
Emotional face processing is critically modulated by the serotonergic system, and serotonin (5-HT) receptor agonists impair emotional face processing. However, the specific contribution of the 5-HT1A receptor remains poorly understood. Here we investigated the spatiotemporal brain mechanisms underpinning the modulation of emotional face processing induced by buspirone, a partial 5-HT1A receptor agonist. In a psychophysical discrimination of emotional faces task, we observed that the discrimination fearful versus neutral faces were reduced, but not happy versus neutral faces. Electrical neuroimaging analyses were applied to visual evoked potentials elicited by emotional face images, after placebo and buspirone administration. Buspirone modulated response strength (i.e., global field power) in the interval 230-248ms after stimulus onset. Distributed source estimation over this time interval revealed that buspirone decreased the neural activity in the right dorsolateral prefrontal cortex that was evoked by fearful faces. These results indicate temporal and valence-specific effects of buspirone on the neuronal correlates of emotional face processing. Furthermore, the reduced neural activity in the dorsolateral prefrontal cortex in response to fearful faces suggests a reduced attention to fearful faces. Collectively, these findings provide new insights into the role of 5-HT1A receptors in emotional face processing and have implications for affective disorders that are characterized by an increased attention to negative stimuli.
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Affiliation(s)
- Fosco Bernasconi
- Neuropsychopharmacology and Brain Imaging Unit, University Hospital of Psychiatry, University of Zurich, 8050 Zurich, Switzerland; Center for Neuroprosthethics, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland; Laboratory of Cognitive Neuroscience, Brain Mind Institute, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.
| | - Michael Kometer
- Neuropsychopharmacology and Brain Imaging Unit, University Hospital of Psychiatry, University of Zurich, 8050 Zurich, Switzerland
| | - Thomas Pokorny
- Neuropsychopharmacology and Brain Imaging Unit, University Hospital of Psychiatry, University of Zurich, 8050 Zurich, Switzerland
| | - Erich Seifritz
- Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric Hospital, University of Zurich, 8050 Zurich, Switzerland
| | - Franz X Vollenweider
- Neuropsychopharmacology and Brain Imaging Unit, University Hospital of Psychiatry, University of Zurich, 8050 Zurich, Switzerland; Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric Hospital, University of Zurich, 8050 Zurich, Switzerland
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Motomura Y, Takeshita A, Egashira Y, Nishimura T, Kim YK, Watanuki S. Interaction between valence of empathy and familiarity: is it difficult to empathize with the positive events of a stranger? J Physiol Anthropol 2015; 34:13. [PMID: 25858485 PMCID: PMC4377041 DOI: 10.1186/s40101-015-0049-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Accepted: 02/14/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Empathy in humans is thought to have evolved via social interactions caused by the formation of social groups. Considering the role of empathy within a social group, there might be a difference between emotional empathy for strangers and familiar others belonging to the same social group. In this study, we used the global field power (GFP) index to investigate empathic brain activity during observation of a cue indicating either a negative or positive image viewed by a stranger or close friend. METHODS Sixteen healthy participants observed a partner performing an emotional gambling task displayed on a monitor. After the partner's choice-response, a frowning or smiling face symbol was simultaneously presented to the participant's monitor while a negative or positive emotional image was presented to the partner's monitor. All participants observed a control condition (CT) showing a computer trial, a stranger-observation condition (SO) showing the trial of a stranger, and a friend-observation condition (FO) to observe the trial of a close friend. During these observations, participants' event-related potentials (ERPs) were recorded to calculate GFP, and after the task, a subjective assessment of their feelings was measured. RESULTS Positive emotion was significantly larger under the FO compared to the CT and the SO. Significantly larger negative emotion was found under the SO and FO compared to the CT. In response to a positive cue, significantly larger GFP during 300 to 600 ms was observed under the FO compared to the CT and SO. In response to a negative cue, significantly larger GFP was observed under the FO and SO compared to the CT. A significantly larger GFP under the SO was found in response to only a negative cue. Topographic map analysis suggested that these differences were related to frontal-occipital dynamics. GFP was significantly correlated with empathic trait. CONCLUSION These results revealed that familiarity with another person has different effects depending on the valence of empathy. Negative empathy, including the danger perception function, might easily occur even among strangers, whereas positive empathy related to nursing and supporting an inner group does not happen easily with strangers.
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Halberstadt AL. Recent advances in the neuropsychopharmacology of serotonergic hallucinogens. Behav Brain Res 2015; 277:99-120. [PMID: 25036425 PMCID: PMC4642895 DOI: 10.1016/j.bbr.2014.07.016] [Citation(s) in RCA: 189] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2014] [Revised: 07/07/2014] [Accepted: 07/08/2014] [Indexed: 12/12/2022]
Abstract
Serotonergic hallucinogens, such as (+)-lysergic acid diethylamide, psilocybin, and mescaline, are somewhat enigmatic substances. Although these drugs are derived from multiple chemical families, they all produce remarkably similar effects in animals and humans, and they show cross-tolerance. This article reviews the evidence demonstrating the serotonin 5-HT2A receptor is the primary site of hallucinogen action. The 5-HT2A receptor is responsible for mediating the effects of hallucinogens in human subjects, as well as in animal behavioral paradigms such as drug discrimination, head twitch response, prepulse inhibition of startle, exploratory behavior, and interval timing. Many recent clinical trials have yielded important new findings regarding the psychopharmacology of these substances. Furthermore, the use of modern imaging and electrophysiological techniques is beginning to help unravel how hallucinogens work in the brain. Evidence is also emerging that hallucinogens may possess therapeutic efficacy.
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Affiliation(s)
- Adam L Halberstadt
- Department of Psychiatry, University of California San Diego, La Jolla, CA, United States.
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