Imperial College London

Dr Robin Carhart-Harris

Faculty of MedicineDepartment of Brain Sciences

Research Fellow
 
 
 
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Contact

 

+44 (0)20 7594 7992r.carhart-harris

 
 
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Assistant

 

Miss Bruna Cunha +44 (0)20 7594 7992

 
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Location

 

Burlington DanesHammersmith Campus

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Summary

 

Publications

Publication Type
Year
to

119 results found

Simonsson O, Hendricks PS, Carhart-Harris R, Kettner H, Osika Wet al., 2021, Association Between Lifetime Classic Psychedelic Use and Hypertension in the Past Year., Hypertension, Vol: 77, Pages: 1510-1516

[Figure: see text].

Journal article

Carhart-Harris RL, Wagner AC, Agrawal M, Kettner H, Rosenbaum JF, Gazzaley A, Nutt DJ, Erritzoe Det al., 2021, Can pragmatic research, real-world data and digital technologies aid the development of psychedelic medicine?, JOURNAL OF PSYCHOPHARMACOLOGY, ISSN: 0269-8811

Journal article

Carhart-Harris R, Giribaldi B, Watts R, Baker-Jones M, Murphy-Beiner A, Murphy R, Martell J, Blemings A, Erritzoe D, Nutt DJet al., 2021, Trial of Psilocybin versus Escitalopram for Depression, NEW ENGLAND JOURNAL OF MEDICINE, Vol: 384, Pages: 1402-1411, ISSN: 0028-4793

Journal article

Jobst BM, Atasoy S, Ponce-Alvarez A, Sanjuan A, Roseman L, Kaelen M, Carhart-Harris R, Kringelbach ML, Deco Get al., 2021, Increased sensitivity to strong perturbations in a whole-brain model of LSD, NEUROIMAGE, Vol: 230, ISSN: 1053-8119

Journal article

Kettner HS, Rosas F, Timmermann C, Kärtner L, Carhart-Harris RL, Roseman Let al., 2021, Psychedelic Communitas: intersubjective experience during psychedelic group sessions predicts enduring changes in psychological wellbeing and social connectedness, Frontiers in Pharmacology, Vol: 12, ISSN: 1663-9812

Background: Recent years have seen a resurgence of research on the potential of psychedelic substances to treat addictive and mood disorders. Historically and contemporarily, psychedelic studies have emphasized the importance of contextual elements ('set and setting') in modulating acute drug effects, and ultimately, influencing long-term outcomes. Nevertheless, current small-scale clinical and laboratory studies have tended to bypass a ubiquitous contextual feature of naturalistic psychedelic use: its social dimension. This study introduces and psychometrically validates an adapted Communitas Scale, assessing acute relational experiences of perceived togetherness and shared humanity, in order to investigate psychosocial mechanisms pertinent to psychedelic ceremonies and retreats.Methods: In this observational, web-based survey study, participants (N = 886) were measured across five successive time-points: 2 weeks before, hours before, and the day after a psychedelic ceremony; as well as the day after, and 4 weeks after leaving the ceremony location. Demographics, psychological traits and state variables were assessed pre-ceremony, in addition to changes in psychological wellbeing and social connectedness from before to after the retreat, as primary outcomes. Using correlational and multiple regression (path) analyses, predictive relationships between psychosocial 'set and setting' variables, communitas, and long-term outcomes were explored.Results: The adapted Communitas Scale demonstrated substantial internal consistency (Cronbach's alpha = 0.92) and construct validity in comparison with validated measures of intra-subjective (visual, mystical, challenging experiences questionnaires) and inter-subjective (perceived emotional synchrony, identity fusion) experiences. Furthermore, communitas during ceremony was significantly correlated with increases in psychological wellbeing (r = 0.22), social connectedness (r = 0.25), and other salient mental health outcomes. Path

Journal article

Szigeti B, Kartner L, Blemings A, Rosas F, Feilding A, Nutt DJ, Carhart-Harris RL, Erritzoe Det al., 2021, Self-blinding citizen science to explore psychedelic microdosing, ELIFE, Vol: 10, ISSN: 2050-084X

Journal article

Pallavicini C, Cavanna F, Zamberlan F, de la Fuente LA, Ilksoy Y, Perl YS, Arias M, Romero C, Carhart-Harris R, Timmermann C, Tagliazucchi Eet al., 2021, Neural and subjective effects of inhaled N,N-dimethyltryptamine in natural settings, JOURNAL OF PSYCHOPHARMACOLOGY, Vol: 35, Pages: 406-420, ISSN: 0269-8811

Journal article

Lawrence DW, Sharma B, Griffiths RR, Carhart-Harris Ret al., 2021, Trends in the Top-Cited Articles on Classic Psychedelics, JOURNAL OF PSYCHOACTIVE DRUGS, ISSN: 0279-1072

Journal article

Roseman L, Ron Y, Saca A, Ginsberg N, Luan L, Karkabi N, Doblin R, Carhart-Harris Ret al., 2021, Relational processes in Ayahuasca groups of Palestinians and Israelis, Frontiers in Pharmacology, ISSN: 1663-9812

Psychedelics are used in many group contexts. However, most phenomenological research on psychedelics is focused on personal experiences. This paper presents a phenomenological investigation centred on intersubjective and intercultural relational processes, exploring how an intercultural context affects both the group and individual process. Through 31 in-depth interviews, ceremonies in which Palestinians and Israelis drink ayahuasca together have been investigated. The overarching question guiding this inquiry was how psychedelics might contribute to processes of peacebuilding, and in particular how an intercultural context, embedded in a protracted conflict, would affect the group’s psychedelic process in a relational sense. Analysis of the interviews was based on grounded theory. Three relational themes about multiocal participatory events which occurred during ayahuasca rituals have emerged from the interviews: (1) Unity-Based Connection – collective events in which a feeling of unity and ‘oneness’ is experienced, whereby participants related to each other based upon a sense of shared humanity, and other social identities seemed to dissolve (such as national and religious identities). (2) Recognition and Difference-Based Connection – events where a strong connection was made to the other culture. These events occurred through the expression of the other culture or religion through music or prayers, which resulted in feelings of awe and reverence (3) Conflict-related revelations – events where participants revisited personal or historical traumatic elements related to the conflict, usually through visions. These events were triggered by the presence of ‘the Other’, and there was a political undertone in those personal visions. This inquiry has revealed that psychedelic ceremonies have the potential to contribute to peacebuilding. This can happen not just by ‘dissolution of identities’, but also by provid

Journal article

Nutt D, Carhart-Harris R, 2021, The Current Status of Psychedelics in Psychiatry, JAMA PSYCHIATRY, Vol: 78, Pages: 121-122, ISSN: 2168-622X

Journal article

Kaertner L, Steinborn M, Kettner H, Spriggs M, Roseman L, Buchborn T, Timmermann Slater C, Erritzoe D, Carhart-Harris Ret al., 2021, Positive expectations predict improved mental-health outcomes linked to psychedelic microdosing, Scientific Reports, Vol: 11, ISSN: 2045-2322

Psychedelic microdosing describes the ingestion of near-threshold perceptible doses of classicpsychedelic substances. Anecdotal reports and observational studies suggest that microdosingmay promote positive mood and well-being, but recent placebo-controlled studies failed to fndcompelling evidence for this. The present study collected web-based mental health and related datausing a prospective (before, during and after) design. Individuals planning a weekly microdosingregimen completed surveys at strategic timepoints, spanning a core four-week test period. Eightyone participants completed the primary study endpoint. Results revealed increased self-reportedpsychological well-being, emotional stability and reductions in state anxiety and depressivesymptoms at the four-week primary endpoint, plus increases in psychological resilience, socialconnectedness, agreeableness, nature relatedness and aspects of psychological fexibility. However,positive expectancy scores at baseline predicted subsequent improvements in well-being, suggestiveof a signifcant placebo response. This study highlights a role for positive expectancy in predictingpositive outcomes following psychedelic microdosing and cautions against zealous inferences on itsputative therapeutic value.

Journal article

Sanz C, Pallavicini C, Carrillo F, Zamberlan F, Sigman M, Mota N, Copelli M, Ribeiro S, Nutt D, Carhart-Harris R, Tagliazucchi Eet al., 2021, The entropic tongue: Disorganization of natural language under LSD, CONSCIOUSNESS AND COGNITION, Vol: 87, ISSN: 1053-8100

Journal article

Andersen KAA, Carhart-Harris R, Nutt DJ, Erritzoe Det al., 2020, Therapeutic effects of classic serotonergic psychedelics: A systematic review of modern-era clinical studies, ACTA PSYCHIATRICA SCANDINAVICA, Vol: 143, Pages: 101-118, ISSN: 0001-690X

Journal article

Rosas FE, Mediano PAM, Jensen HJ, Seth AK, Barrett AB, Carhart-Harris RL, Bor Det al., 2020, Reconciling emergences: An information-theoretic approach to identify causal emergence in multivariate data, PLOS COMPUTATIONAL BIOLOGY, Vol: 16, ISSN: 1553-734X

Journal article

Luppi AI, Mediano PAM, Rosas FE, Allanson J, Pickard JD, Carhart-Harris RL, Williams GB, Craig MM, Finoia P, Owen AM, Naci L, Menon DK, Bor D, Stamatakis EAet al., 2020, A Synergistic Workspace for Human Consciousness Revealed by Integrated Information Decomposition

<jats:title>Abstract</jats:title><jats:p>A central goal of neuroscience is to understand how the brain synthesises information from multiple inputs to give rise to a unified conscious experience. This process is widely believed to require integration of information. Here, we combine information theory and network science to address two fundamental questions: how is the human information-processing architecture functionally organised? And how does this organisation support human consciousness? To address these questions, we leverage the mathematical framework of Integrated Information Decomposition to delineate a cognitive architecture wherein specialised modules interact with a “synergistic global workspace,” comprising functionally distinct gateways and broadcasters. Gateway regions gather information from the specialised modules for processing in the synergistic workspace, whose contents are then further integrated to later be made widely available by broadcasters. Through data-driven analysis of resting-state functional MRI, we reveal that gateway regions correspond to the brain’s well-known default mode network, whereas broadcasters of information coincide with the executive control network. Demonstrating that this synergistic workspace supports human consciousness, we further apply Integrated Information Decomposition to BOLD signals to compute integrated information across the brain. By comparing changes due to propofol anaesthesia and severe brain injury, we demonstrate that most changes in integrated information happen within the synergistic workspace. Furthermore, it was found that loss of consciousness corresponds to reduced integrated information between gateway, but not broadcaster, regions of the synergistic workspace. Thus, loss of consciousness may coincide with breakdown of information integration by this synergistic workspace of the human brain. Together, these findings demonstrate that refining our understanding

Journal article

Brouwer A, Carhart-Harris RL, 2020, Pivotal mental states, JOURNAL OF PSYCHOPHARMACOLOGY, Vol: 35, Pages: 319-352, ISSN: 0269-8811

Journal article

Leptourgos P, Fortier-Davy M, Carhart-Harris R, Corlett PR, Dupuis D, Halberstadt AL, Kometer M, Kozakova E, Laroi F, Noorani TN, Preller KH, Waters F, Zaytseva Y, Jardri Ret al., 2020, Hallucinations Under Psychedelics and in the Schizophrenia Spectrum: An Interdisciplinary and Multiscale Comparison, SCHIZOPHRENIA BULLETIN, Vol: 46, Pages: 1396-1408, ISSN: 0586-7614

Journal article

Herzog R, Mediano PAM, Rosas FE, Carhart-Harris R, Perl YS, Tagliazucchi E, Cofre Ret al., 2020, A mechanistic model of the neural entropy increase elicited by psychedelic drugs, Scientific Reports, Vol: 10, ISSN: 2045-2322

Psychedelic drugs, including lysergic acid diethylamide and other agonists of the serotonin 2A receptor (5HT2A-R), induce drastic changes in subjective experience, and provide a unique opportunity to study the neurobiological basis of consciousness. One of the most notable neurophysiological signatures of psychedelics, increased entropy in spontaneous neural activity, is thought to be of relevance to the psychedelic experience, mediating both acute alterations in consciousness and long-term effects. However, no clear mechanistic explanation for this entropy increase has been put forward so far. We sought to do this here by building upon a recent whole-brain model of serotonergic neuromodulation, to study the entropic effects of 5HT2A-R activation. Our results reproduce the overall entropy increase observed in previous experiments in vivo, providing the first model-based explanation for this phenomenon. We also found that entropy changes were not uniform across the brain: entropy increased in some regions and decreased in others, suggesting a topographical reconfiguration mediated by 5HT2A-R activation. Interestingly, at the whole-brain level, this reconfiguration was not well explained by 5HT2A-R density, but related closely to the topological properties of the brain's anatomical connectivity. These results help us understand the mechanisms underlying the psychedelic state and, more generally, the pharmacological modulation of whole-brain activity.

Journal article

Varley TF, Carhart-Harris R, Roseman L, Menon DK, Stamatakis EAet al., 2020, Serotonergic psychedelics LSD & psilocybin increase the fractal dimension of cortical brain activity in spatial and temporal domains, NEUROIMAGE, Vol: 220, ISSN: 1053-8119

Journal article

Alamia A, Timmermann C, VanRullen R, Carhart-Harris RLet al., 2020, DMT alters cortical travelling waves, eLife, Vol: 9, Pages: 1-16, ISSN: 2050-084X

Psychedelic drugs are potent modulators of conscious states and therefore powerful tools for investigating their neurobiology. N,N, Dimethyltryptamine (DMT) can rapidly induce an extremely immersive state of consciousness characterized by vivid and elaborate visual imagery. Here, we investigated the electrophysiological correlates of the DMT-induced altered state from a pool of participants receiving DMT and (separately) placebo (saline) while instructed to keep their eyes closed. Consistent with our hypotheses, results revealed a spatio-temporal pattern of cortical activation (i.e. travelling waves) similar to that elicited by visual stimulation. Moreover, the typical top-down alpha-band rhythms of closed-eyes rest were significantly decreased, while the bottom-up forward wave was significantly increased. These results support a recent model proposing that psychedelics reduce the ‘precision-weighting of priors’, thus altering the balance of top-down versus bottom-up information passing. The robust hypothesis-confirming nature of these findings imply the discovery of an important mechanistic principle underpinning psychedelic-induced altered states.

Journal article

Spriggs MJ, Kettner H, Carhart-Harris RL, 2020, Positive effects of psychedelics on depression and wellbeing scores in individuals reporting an eating disorder, EATING AND WEIGHT DISORDERS-STUDIES ON ANOREXIA BULIMIA AND OBESITY, Vol: 26, Pages: 1265-1270, ISSN: 1124-4909

Journal article

Zeifman R, Wagner A, Watts R, Kettner H, Mertens L, Carhart-Harris Ret al., 2020, Post-psychedelic reductions in experiential avoidance are associated with decreases in depression severity and suicidal ideation, Frontiers in Psychiatry, Vol: 11, Pages: 1-13, ISSN: 1664-0640

Psychedelic therapy shows promise as a novel intervention for a wide range of mental health concerns but its therapeutic action is incompletely understood. In line with acceptance and commitment therapy’s (ACT’s) transdiagnostic model, qualitative research has suggested that reductions in experiential avoidance are an important component of therapeutic outcomes associated with psychedelics. However, limited research has quantitatively explored the association between decreases in experiential avoidance and therapeutic outcomes associated with psychedelics. Therefore, in two prospective studies, using convenience samples of individuals with plans to use a psychedelic, we explored the impact of psychedelic use on experiential avoidance, depression severity, and suicidal ideation, as well as relationships between changes in these outcomes. Participants (Study 1, N=104; Study 2, N=254) completed self-report questionnaires of depression severity, suicidal ideation, and experiential avoidance: 1) before using a psychedelic (in ceremonial and non-ceremonial contexts), as well as 2) 2-weeks and 3) 4-weeks after psychedelic use. Across both studies, repeated measures ANOVAs indicated significant decreases in experiential avoidance, depression severity, and suicidal ideation after psychedelic use. Furthermore, decreases in experiential avoidance were significantly associated with decreases in depression severity and suicidal ideation. These results suggest that psychedelics may lead to significant decreases in experiential avoidance, depression severity, and suicidal ideation. Additionally, these findings imply that reduced experiential avoidance may be a transdiagnostic mechanism mediating treatment success within psychedelic therapy. We conclude that integrating psychedelics with psychotherapeutic interventions that target experiential avoidance (e.g. ACT) may enhance therapeutic outcomes.

Journal article

Carhart-Harris R, 2020, PSYCHEDELICS: THERAPEUTIC MECHANISMS, Annual Meeting of the British-NeuroPsychiatry-Association (BNPA), Publisher: BMJ PUBLISHING GROUP, ISSN: 0022-3050

Conference paper

Borissova A, Ferguson B, Wall MB, Morgan CJA, Carhart-Harris RL, Bolstridge M, Bloomfield MAP, Williams TM, Feilding A, Murphy K, Tyacke RJ, Erritzoe D, Stewart L, Wolff K, Nutt D, Curran HV, Lawn Wet al., 2020, Acute effects of MDMA on trust, cooperative behaviour and empathy: A double-blind, placebo-controlled experiment, JOURNAL OF PSYCHOPHARMACOLOGY, ISSN: 0269-8811

Journal article

Herzog R, Mediano PAM, Rosas FE, Carhart-Harris R, Perl YS, Tagliazucchi E, Cofre Ret al., 2020, A mechanistic model of the neural entropy increase elicited by psychedelic drugs, Publisher: Cold Spring Harbor Laboratory

<jats:title>ABSTRACT</jats:title><jats:p>Psychedelic drugs, including lysergic acid diethylamide (LSD) and other agonists of the serotonin 2A receptor (5HT2A-R), induce drastic changes in subjective experience, and provide a unique opportunity to study the neurobiological basis of consciousness. One of the most notable neurophysiological signatures of psychedelics, increased entropy in spontaneous neural activity, is thought to be of relevance to the psychedelic experience, encoding both acute alterations in consciousness and mediating long-term effects. However, no clear mechanistic explanation for this ‘entropic’ phenomenon has been put forward so far. We sought to do this here by building upon a recent whole-brain model of serotonergic neuromodulation, to study the entropic effects of 5HT2A-R activation. Our results reproduce the overall entropy increase observed in previous experiments <jats:italic>in vivo</jats:italic>, providing the first model-based explanation for this phenomenon. We also found that entropy changes were not uniform across the brain: entropy increased in some regions and decreased in others, suggesting a topographical reconfiguration mediated by 5HT2A-R activation. Interestingly, at the whole-brain level, this reconfiguration was not well explained by 5HT2A-R density, but related closely to the topological properties of the brain’s anatomical connectivity. These results help us understand the mechanisms underlying the psychedelic state and, more generally, the pharmacological modulation of whole-brain activity.</jats:p>

Working paper

Kringelbach ML, Cruzat J, Cabral J, Knudsen GM, Carhart-Harris R, Whybrow PC, Logothetis NK, Deco Get al., 2020, Dynamic coupling of whole-brain neuronal and neurotransmitter systems, Proceedings of the National Academy of Sciences of USA, Vol: 117, Pages: 9566-9576, ISSN: 0027-8424

Remarkable progress has come from whole-brain models linking anatomy and function. Paradoxically, it is not clear how a neuronal dynamical system running in the fixed human anatomical connectome can give rise to the rich changes in the functional repertoire associated with human brain function, which is impossible to explain through long-term plasticity. Neuromodulation evolved to allow for such flexibility by dynamically updating the effectivity of the fixed anatomical connectivity. Here, we introduce a theoretical framework modeling the dynamical mutual coupling between the neuronal and neurotransmitter systems. We demonstrate that this framework is crucial to advance our understanding of whole-brain dynamics by bidirectional coupling of the two systems through combining multimodal neuroimaging data (diffusion magnetic resonance imaging [dMRI], functional magnetic resonance imaging [fMRI], and positron electron tomography [PET]) to explain the functional effects of specific serotoninergic receptor (5-HT2AR) stimulation with psilocybin in healthy humans. This advance provides an understanding of why psilocybin is showing considerable promise as a therapeutic intervention for neuropsychiatric disorders including depression, anxiety, and addiction. Overall, these insights demonstrate that the whole-brain mutual coupling between the neuronal and the neurotransmission systems is essential for understanding the remarkable flexibility of human brain function despite having to rely on fixed anatomical connectivity.

Journal article

Nutt D, Erritzoe D, Carhart-Harris R, 2020, Psychedelic Psychiatry's Brave New World, CELL, Vol: 181, Pages: 24-28, ISSN: 0092-8674

Journal article

Close JB, Hajien EC, Watts R, Roseman L, Carhart-Harris RLet al., 2020, Psychedelics and psychological flexibility - Results of a prospective web-survey using the Acceptance and Action Questionnaire II, JOURNAL OF CONTEXTUAL BEHAVIORAL SCIENCE, Vol: 16, Pages: 37-44, ISSN: 2212-1447

Journal article

Mertens LJ, Wall MB, Roseman L, Demetriou L, Nutt DJ, Carhart-Harris RLet al., 2020, Therapeutic mechanisms of psilocybin: Changes in amygdala and prefrontal functional connectivity during emotional processing after psilocybin for treatment-resistant depression, JOURNAL OF PSYCHOPHARMACOLOGY, Vol: 34, Pages: 167-180, ISSN: 0269-8811

Journal article

Kettner H, Gandy S, Haijen E, Carhart-Harris Ret al., 2019, From egoism to ecoism: psychedelics increase nature relatedness in a state-mediated and context-dependent manner, International Journal of Environmental Research and Public Health, Vol: 16, Pages: 1-23, ISSN: 1660-4601

(1) Background: There appears to be a growing disconnection between humans and their natural environments which has been linked to poor mental health and ecological destruction. Previous research suggests that individual levels of nature relatedness can be increased through the use of classical psychedelic compounds, although a causal link between psychedelic use and nature relatedness has not yet been established. (2) Methods: Using correlations and generalized linear mixed regression modelling, we investigated the association between psychedelic use and nature relatedness in a prospective online study. Individuals planning to use a psychedelic received questionnaires 2 weeks before (N = 654), plus one day, 2 weeks, 4 weeks, and 2 years after a psychedelic experience. (3) Results: Frequency of lifetime psychedelic use was positively correlated with nature relatedness at baseline. Nature relatedness was significantly increased 2 weeks, 4 weeks and 2 years after the psychedelic experience. This increase was positively correlated with concomitant increases in psychological well-being and dependent on the extent of ego-dissolution and the perceived influence of natural surroundings during the acute psychedelic state. (4) Conclusions: The here presented evidence for a context- and state-dependent causal effect of psychedelic use on nature relatedness bears relevance for psychedelic treatment models in mental health and, in the face of the current ecological crisis, planetary health.

Journal article

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