103 results found
<jats:p>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.</jats:p>
Leptourgos P, Fortier-Davy M, Carhart-Harris R, et al., 2020, Hallucinations Under Psychedelics and in the Schizophrenia Spectrum: An Interdisciplinary and Multiscale Comparison., Schizophr Bull
The recent renaissance of psychedelic science has reignited interest in the similarity of drug-induced experiences to those more commonly observed in psychiatric contexts such as the schizophrenia-spectrum. This report from a multidisciplinary working group of the International Consortium on Hallucinations Research (ICHR) addresses this issue, putting special emphasis on hallucinatory experiences. We review evidence collected at different scales of understanding, from pharmacology to brain-imaging, phenomenology and anthropology, highlighting similarities and differences between hallucinations under psychedelics and in the schizophrenia-spectrum disorders. Finally, we attempt to integrate these findings using computational approaches and conclude with recommendations for future research.
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, ISSN: 1124-4909
Zeifman R, Wagner A, Watts R, et 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.
Carhart-Harris R, 2020, PSYCHEDELICS: THERAPEUTIC MECHANISMS, Annual Meeting of the British-NeuroPsychiatry-Association (BNPA), Publisher: BMJ PUBLISHING GROUP, ISSN: 0022-3050
Nutt D, Carhart-Harris R, 2020, The Current Status of Psychedelics in Psychiatry., JAMA Psychiatry
Varley TF, Carhart-Harris R, Roseman L, et al., 2020, Serotonergic psychedelics LSD & psilocybin increase the fractal dimension of cortical brain activity in spatial and temporal domains., Neuroimage, Vol: 220
Psychedelic drugs, such as psilocybin and LSD, represent unique tools for researchers investigating the neural origins of consciousness. Currently, the most compelling theories of how psychedelics exert their effects is by increasing the complexity of brain activity and moving the system towards a critical point between order and disorder, creating more dynamic and complex patterns of neural activity. While the concept of criticality is of central importance to this theory, few of the published studies on psychedelics investigate it directly, testing instead related measures such as algorithmic complexity or Shannon entropy. We propose using the fractal dimension of functional activity in the brain as a measure of complexity since findings from physics suggest that as a system organizes towards criticality, it tends to take on a fractal structure. We tested two different measures of fractal dimension, one spatial and one temporal, using fMRI data from volunteers under the influence of both LSD and psilocybin. The first was the fractal dimension of cortical functional connectivity networks and the second was the fractal dimension of BOLD time-series. In addition to the fractal measures, we used a well-established, non-fractal measure of signal complexity and show that they behave similarly. We were able to show that both psychedelic drugs significantly increased the fractal dimension of functional connectivity networks, and that LSD significantly increased the fractal dimension of BOLD signals, with psilocybin showing a non-significant trend in the same direction. With both LSD and psilocybin, we were able to localize changes in the fractal dimension of BOLD signals to brain areas assigned to the dorsal-attenion network. These results show that psychedelic drugs increase the fractal dimension of activity in the brain and we see this as an indicator that the changes in consciousness triggered by psychedelics are associated with evolution towards a critical zone.
Borissova A, Ferguson B, Wall MB, et al., 2020, Acute effects of MDMA on trust, cooperative behaviour and empathy: A double-blind, placebo-controlled experiment, JOURNAL OF PSYCHOPHARMACOLOGY, ISSN: 0269-8811
Kringelbach ML, Cruzat J, Cabral J, et al., 2020, Dynamic coupling of whole-brain neuronal and neurotransmitter systems, PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, Vol: 117, Pages: 9566-9576, ISSN: 0027-8424
Nutt D, Erritzoe D, Carhart-Harris R, 2020, Psychedelic Psychiatry's Brave New World, CELL, Vol: 181, Pages: 24-28, ISSN: 0092-8674
Close JB, Hajien EC, Watts R, et 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
Mertens LJ, Wall MB, Roseman L, et 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
Kettner H, Gandy S, Haijen E, et al., From egoism to ecoism: psychedelics increase nature relatedness in a state-mediated and context-dependent manner, International Journal of Environmental Research and Public Health, 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.
Mertens LJ, Wall MB, Roseman L, et al., 2019, Therapeutic mechanisms of psychedelic drugs: Changes in amygdala and prefrontal functional connectivity during emotional processing after psilocybin for treatment-resistant depression, 32nd Congress of the European-College-of-Neuropsychopharmacology (ECNP), Publisher: ELSEVIER, Pages: S416-S417, ISSN: 0924-977X
Timmermann Slater CB, Roseman L, Schartner M, et al., 2019, Neural correlates of the DMT experience as assessed with multivariate EEG, Scientific Reports, Vol: 9, Pages: 1-13, ISSN: 2045-2322
Studying transitions in and out of the altered state of consciousness caused by intravenous (IV) N,N-Dimethyltryptamine (DMT - a fast-acting tryptamine psychedelic) offers a safe and powerful means of advancing knowledge on the neurobiology of conscious states. Here we sought to investigate the effects of IV DMT on the power spectrum and signal diversity of human brain activity (6 female, 7 male) recorded via multivariate EEG, and plot relationships between subjective experience, brain activity and drug plasma concentrations across time. Compared with placebo, DMT markedly reduced oscillatory power in the alpha and beta bands and robustly increased spontaneous signal diversity. Time-referenced neurophenomenological analyses revealed close relationships between changes in various aspects of subjective experience and changes in brain activity. Importantly, the emergence of oscillatory activity within the delta and theta frequency bands was found to correlate with the peak of the experience - particularly its eyes-closed visual component. These findings highlight marked changes in oscillatory activity and signal diversity with DMT that parallel broad and specific components of the subjective experience, thus advancing our understanding of the neurobiological underpinnings of immersive states of consciousness.
Russ SL, Carhart-Harris RL, Maruyama G, et al., 2019, Replication and extension of a model predicting response to psilocybin, PSYCHOPHARMACOLOGY, Vol: 236, Pages: 3221-3230, ISSN: 0033-3158
Roseman L, 2019, Functional imaging investigation of psychedelic visual imagery
Psychedelics can induce eyes-closed imagery in which various visions can be experienced. These visions vary from simple geometrical patterns, to more complex imagery, to full immersion within “other realms”. Past studies suggest that the visual cortex is involved in processing these visions, yet these studies were limited into investigation of activity. In this thesis, the aim was to expand on the involvement of the visual cortex by investigating processes that are beyond simple activation maps, such as functional connectivity and dynamics. In study 1, it was hypothesized that the visual cortex will show increased functional connectivity with many cortical and subcortical regions. This was investigated with 15 subjects that were scanned using fMRI under the influence of 75 µg of LSD or placebo. The results of this study showed increased resting state functional connectivity (RSFC) between the primary visual cortex and many cortical and subcortical regions. This result correlated with subjective ratings of psychedelic imagery and with occipital alpha power suppression measured with MEG, which is a reliable neural correlate of the intensity of the psychedelic state. It study 2, it was hypothesized that connectivity within the visual cortex would match its retinotopic architecture. Retinotopic mapping is the representation of the visual field (the world we observe) in the visual cortex – e.g. areas which are near to each other in the visual field will be near each other in the visual cortex. In this study, it was found that under LSD (same procedure as study 1), with eyes closed, connectivity patterns between different subregions of the visual cortex matched the retinotopic mapping of these regions, suggesting that the visual system behaves as if it is seeing spatially localized input, with eyes-closed under LSD. In study 3, it was hypothesized that during the onset phase of psychedelic imagery, the activation of subregions of the visual cortex
Lord L-D, Expert P, Atasoy S, et al., 2019, Dynamical exploration of the repertoire of brain networks at rest is modulated by psilocybin, NeuroImage, Vol: 199, Pages: 127-142, ISSN: 1053-8119
Growing evidence from the dynamical analysis of functional neuroimaging data suggests that brain function can be understood as the exploration of a repertoire of metastable connectivity patterns ('functional brain networks'), which potentially underlie different mental processes. The present study characterizes how the brain's dynamical exploration of resting-state networks is rapidly modulated by intravenous infusion of psilocybin, a tryptamine psychedelic found in "magic mushrooms". We employed a data-driven approach to characterize recurrent functional connectivity patterns by focusing on the leading eigenvector of BOLD phase coherence at single-TR resolution. Recurrent BOLD phase-locking patterns (PL states) were assessed and statistically compared pre- and post-infusion of psilocybin in terms of their probability of occurrence and transition profiles. Results were validated using a placebo session. Recurrent BOLD PL states revealed high spatial overlap with canonical resting-state networks. Notably, a PL state forming a frontoparietal subsystem was strongly destabilized after psilocybin injection, with a concomitant increase in the probability of occurrence of another PL state characterized by global BOLD phase coherence. These findings provide evidence of network-specific neuromodulation by psilocybin and represent one of the first attempts at bridging molecular pharmacodynamics and whole-brain network dynamics.
Timmermann C, Roseman L, Schartner M, et al., 2019, Neural correlates of the DMT experience as assessed via multivariate EEG, Publisher: Cold Spring Harbor Laboratory
<jats:title>Abstract</jats:title><jats:p>Studying transitions in and out of the altered state of consciousness caused by intravenous (IV) N,N-Dimethyltryptamine (DMT – a fast-acting tryptamine psychedelic) offers a safe and powerful means of advancing knowledge on the neurobiology of conscious states. Here we sought to investigate the effects of IV DMT on the power spectrum and signal diversity of human brain activity (6 female, 7 male) recorded via multivariate EEG, and plot relationships between subjective experience, brain activity and drug plasma concentrations across time. Compared with placebo, DMT markedly reduced oscillatory power in the <jats:italic>alpha</jats:italic> and <jats:italic>beta</jats:italic> bands and robustly increased spontaneous signal diversity. Time-referenced analyses revealed close relationships between changes in various aspects of subjective experience and changes in brain activity. Importantly, the emergence of oscillatory activity within the delta and theta frequency bands was found to correlate with the peak of the experience, and particularly its eyes-closed visual component. These findings highlight marked changes in oscillatory activity and signal diversity with DMT that parallel broad and specific components of the relevant subjective experience and thus further our understanding of the neurobiological underpinnings of immersive states of consciousness.</jats:p>
Roseman L, Haijen E, Idialu-Ikato K, et al., 2019, Emotional breakthrough and psychedelics: Validation of the Emotional Breakthrough Inventory, Journal of Psychopharmacology, Pages: 026988111985597-026988111985597, ISSN: 0269-8811
<jats:sec><jats:title>Background:</jats:title><jats:p> Psychedelic therapy is gaining recognition and the nature of the psychedelic experience itself has been found to mediate subsequent long-term psychological changes. Much emphasis has been placed on the occurrence of mystical-type experiences in determining long-term responses to psychedelics yet here we demonstrate the importance of another component, namely: emotional breakthrough. </jats:p></jats:sec><jats:sec><jats:title>Methods:</jats:title><jats:p> Three hundred and seventy-nine participants completed online surveys before and after a planned psychedelic experience. Items pertaining to emotional breakthrough were completed one day after the psychedelic experience, as were items comprising the already validated Mystical Experience Questionnaire and the Challenging Experience Questionnaire. Emotional breakthrough, Mystical Experience Questionnaire and Challenging Experience Questionnaire scores were used to predict changes in well-being (Warwick-Edinburgh Mental Wellbeing Scale) in a subsample of 75 participants with low well-being baseline scores (⩽45). </jats:p></jats:sec><jats:sec><jats:title>Results:</jats:title><jats:p> Factor analyses revealed six emotional breakthrough items with high internal consistency (Cronbach’s alpha=0.932) and supported our prior hypothesis that emotional breakthrough is a distinct component of the psychedelic experience. Emotional breakthrough scores behaved dose-dependently, and were higher if the psychedelic was taken with therapeutic planning and intent. Emotional breakthrough, Mystical Experience Questionnaire and Challenging Experience Questionnaire scores combined, significantly predicted subsequent changes in well-being ( r=0.45, p=0.0005, n=75), with each scale contributing significant predictive value. Emotional breakthrough and Mystical Experience Questionnaire scores
Carhart-Harris RL, Friston KJ, 2019, REBUS and the Anarchic Brain: Toward a Unified Model of the Brain Action of Psychedelics, PHARMACOLOGICAL REVIEWS, Vol: 71, Pages: 316-344, ISSN: 0031-6997
Scott G, Carhart-Harris R, 2019, Psychedelics as a treatment for disorders of consciousness, Neuroscience of Consciousness, Vol: 2019, Pages: 1-8, ISSN: 2057-2107
Based on its ability to increase brain complexity, a seemingly reliable index of conscious level, we proposetesting the capacity ofthe classic psychedelic, psilocybin,to increase conscious awarenessin patients with disorders of consciousness.We alsoconfrontthe considerable ethical and practical challengesthis proposal must address, if this hypothesis is to be directly assessed.
Erritzoe D, Smith J, Fisher PM, et al., 2019, Recreational use of psychedelics is associated with elevated personality trait openness: Exploration of associations with brain serotonin markers., J Psychopharmacol, Pages: 269881119827891-269881119827891
BACKGROUND:: Recent studies have suggested therapeutic benefits of psychedelics for a variety of mental health conditions. The understanding of how single psychedelic administrations can induce long-lasting effects are, in large, still lacking. However, recent studies in both healthy and clinical populations suggest a role for personality changes. AIM:: To test support for some of these plausible mechanisms we evaluated (cross-sectional) associations between recreational use of psychedelics and 3,4-methylene-dioxymethamphetamine (MDMA) and (a) personality measures and (b) key markers of cerebral serotonergic signalling (serotonin transporter and serotonin-2A-receptor binding). METHODS:: In 10 psychedelic-preferring recreational users, 14 MDMA-preferring users and 21 non-using controls, personality was assessed using the 'big five' instrument Revised NEO Personality Inventory (NEO-PI-R). Frontal serotonin transporter and serotonin-2A-receptor binding potentials were quantified using [11C]DASB and [18F]altanserin positron emission tomography, respectively. RESULTS:: Of the five NEO-PI-R traits, only openness to experience scores differed between the three groups; psychedelic-preferring recreational users showing higher openness to experience scores when compared with both MDMA-preferring users and controls. Openness to experience scores were positively associated with lifetime number of psychedelic exposures, and among all MDMA-preferring user/psychedelic-preferring recreational user individuals, frontal serotonin transporter binding - but not frontal serotonin-2A-receptor binding - was positively associated with openness to experience. CONCLUSION:: Our findings from this cross-sectional study support increasing evidence of a positive association between psychedelic experiences and openness to experience, and (a) expands this to the context of 'recreational' psychedelics use, and (b) links serotonergic neurotransmission to openness to experience. A modulation of perso
Haijen ECHM, Kaelen M, Roseman L, et al., 2018, Predicting responses to psychedelics: a prospective study, Frontiers in Pharmacology, Vol: 9, ISSN: 1663-9812
Responses to psychedelics are notoriously difficult to predict, yet significant work is currently underway to assess their therapeutic potential and the level of interest in psychedelics among the general public appears to be increasing. We aimed to collect prospective data in order to improve our ability to predict acute- and longer-term responses to psychedelics. Individuals who planned to take a psychedelic through their own initiative participated in an online survey (www.psychedelicsurvey.com). Traits and variables relating to set, setting and the acute psychedelic experience were measured at five different time points before and after the experience. Principle component and regression methods were used to analyse the data. Sample sizes for the five time points included N= 654, N= 535, N= 379, N= 315, and N= 212 respectively. Psychological well-being was increased two weeks after a psychedelic experience and remained at this level after four weeks. This increase was larger for individuals who scored higher for a ‘mystical-type experience’, and smaller for those who scored higher for ‘challenging experience’. Having ‘clear intentions’ for the experience was conducive to mystical-type experiences. Having a positive ‘set’, as well as having the experience with intentions related to ‘recreation’, were both found to decrease the likelihood of having a challenging experience. The trait ‘absorption’ and higher drug doses promoted both mystical-type and challenging experiences. When comparing different types of variables, traits variables seemed to explain most variance in the change in well-being after a psychedelic experience. These results confirm the importance of extra-pharmacological factors in determining responses to a psychedelic. We view this study as an early step towards the development of empirical guidelines that can evolve and improve iteratively with the ultimate purpose of guiding
Carhart-Harris RL, 2018, The entropic brain - revisited, NEUROPHARMACOLOGY, Vol: 142, Pages: 167-178, ISSN: 0028-3908
Roseman L, Demetriou L, Wall M, et al., 2018, Increased amygdala responses to emotional faces after psilocybin for treatment-resistant depression, Neuropharmacology, Vol: 142, Pages: 263-269, ISSN: 0028-3908
Recent evidence indicates that psilocybin with psychological support may be effective for treating depression. Some studies have found that patients with depression show heightened amygdala responses to fearful faces and there is reliable evidence that treatment with SSRIs attenuates amygdala responses (Ma, 2015). We hypothesised that amygdala responses to emotional faces would be altered post-treatment with psilocybin. In this open-label study, 20 individuals diagnosed with moderate to severe, treatment-resistant depression, underwent two separate dosing sessions with psilocybin. Psychological support was provided before, during and after these sessions and 19 completed fMRI scans one week prior to the first session and one day after the second and last. Neutral, fearful and happy faces were presented in the scanner and analyses focused on the amygdala. Group results revealed rapid and enduring improvements in depressive symptoms post psilocybin. Increased responses to fearful and happy faces were observed in the right amygdala post-treatment, and right amygdala increases to fearful versus neutral faces were predictive of clinical improvements at 1-week. Psilocybin with psychological support was associated with increased amygdala responses to emotional stimuli, an opposite effect to previous findings with SSRIs. This suggests fundamental differences in these treatments’ therapeutic actions, with SSRIs mitigating negative emotions and psilocybin allowing patients to confront and work through them. Based on the present results, we propose that psilocybin with psychological support is a treatment approach that potentially revives emotional responsiveness in depression, enabling patients to reconnect with their emotions.
Erritzoe D, Roseman L, Nour MM, et al., 2018, Effects of psilocybin therapy on personality structure, Acta Psychiatrica Scandinavica, Vol: 138, Pages: 368-378, ISSN: 1600-0447
ObjectiveTo explore whether psilocybin with psychological support modulates personality parameters in patients suffering from treatment‐resistant depression (TRD).MethodTwenty patients with moderate or severe, unipolar, TRD received oral psilocybin (10 and 25 mg, one week apart) in a supportive setting. Personality was assessed at baseline and at 3‐month follow‐up using the Revised NEO Personality Inventory (NEO‐PI‐R), the subjective psilocybin experience with Altered State of Consciousness (ASC) scale, and depressive symptoms with QIDS‐SR16.ResultsNeuroticism scores significantly decreased while Extraversion increased following psilocybin therapy. These changes were in the direction of the normative NEO‐PI‐R data and were both predicted, in an exploratory analysis, by the degree of insightfulness experienced during the psilocybin session. Openness scores also significantly increased following psilocybin, whereas Conscientiousness showed trend‐level increases, and Agreeableness did not change.ConclusionOur observation of changes in personality measures after psilocybin therapy was mostly consistent with reports of personality change in relation to conventional antidepressant treatment, although the pronounced increases in Extraversion and Openness might constitute an effect more specific to psychedelic therapy. This needs further exploration in future controlled studies, as do the brain mechanisms of postpsychedelic personality change.
Lyons T, Carhart-Harris RL, 2018, More realistic forecasting of future life events after psilocybin for treatment-resistant depression, Frontiers in Psychology, Vol: 9, ISSN: 1664-1078
Background: Evidence suggests that classical psychedelics can promote enduring changes in personality, attitudes and optimism, as well as improvements in mental health outcomes.Aim: To investigate the effects of a composite intervention, involving psilocybin, on pessimism biases in patients with treatment-resistant depression (TRD).Methods: Patients with TRD (n = 15) and matched, untreated non-depressed controls (n = 15) performed the Prediction Of Future Life Events (POFLE) task. The POFLE task requires participants to predict the likelihood of certain life events occurring within a 30-day period, after which the actual rate of event occurrence is reported; this gives an index of potential pessimism versus optimism bias. Psilocybin was administered in two oral dosing sessions (10 and 25 mg) one week apart. Main outcome measures were collected at baseline and one week after the second dosing session.Results: Patients showed a significant pessimism bias at baseline [t(14) = -3.260, p = 0.006; 95% CI (-0.16, -0.03), g = 1.1] which was related to the severity of their depressive symptoms (rs = -0.55, p = 0.017). One week after psilocybin treatment, this bias was significantly decreased [t(14) = -2.714, p = 0.017; 95% CI (-0.21, -0.02), g = 0.7] and depressive symptoms were greatly improved [t(14) = 7.900, p < 0.001; 95% CI (16.17, 28.23), g = 1.9]; moreover, the magnitude of change in both variables was significantly correlated (r = -0.57, p = 0.014). Importantly, post treatment, patients became significantly more accurate at predicting the occurrence of future life events [t(14) = 1.857, p = 0.042; 95% CI (-0.01, 0.12), g = 0.6] whereas no such change was observed in the control subjects.Conclusion: These findings suggest that psilocybin with psychological support might correct pessimism biases in TRD, enabling a more positive and accurate outlook.
Deco G, Cruzat J, Cabral J, et al., 2018, Whole-Brain Multimodal Neuroimaging Model Using Serotonin Receptor Maps Explains Non-linear Functional Effects of LSD, CURRENT BIOLOGY, Vol: 28, Pages: 3065-+, ISSN: 0960-9822
Near-death experiences (NDEs) are complex subjective experiences, which have been previously associated with the psychedelic experience and more specifically with the experience induced by the potent serotonergic, N,N-Dimethyltryptamine (DMT). Potential similarities between both subjective states have been noted previously, including the subjective feeling of transcending one’s body and entering an alternative realm, perceiving and communicating with sentient ‘entities’ and themes related to death and dying. In this within-subjects placebo-controled study we aimed to test the similarities between the DMT state and NDEs, by administering DMT and placebo to 13 healthy participants, who then completed a validated and widely used measure of NDEs. Results revealed significant increases in phenomenological features associated with the NDE, following DMT administration compared to placebo. Also, we found significant relationships between the NDE scores and DMT-induced ego-dissolution and mystical-type experiences, as well as a significant association between NDE scores and baseline trait ‘absorption’ and delusional ideation measured at baseline. Furthermore, we found a significant overlap in nearly all of the NDE phenomenological features when comparing DMT-induced NDEs with a matched group of ‘actual’ NDE experiencers. These results reveal a striking similarity between these states that warrants further investigation.
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