OPEN Foundation

LSD

LSD-induced increases in social adaptation to opinions similar to one’s own are associated with stimulation of serotonin receptors

Abstract

Adapting one’s attitudes and behaviors to group norms is essential for successful social interaction and, thus, participation in society. Yet, despite its importance for societal and individual functioning, the underlying neuropharmacology is poorly understood. We therefore investigated its neurochemical and neural correlates in a pharmacological functional magnetic resonance imaging study. Lysergic acid diethylamide (LSD) has been shown to alter social processing and therefore provides the unique opportunity to investigate the role of the 5-HT2A receptor in social influence processing. Twenty-four healthy human volunteers received either (1) placebo + placebo, (2) placebo + LSD (100 µg), or (3) the 5-HT2A receptor antagonist ketanserin (40 mg) + LSD (100 µg) at three different occasions in a double-blind, randomized, counterbalanced, cross-over design. LSD increases social adaptation but only if the opinions of others are similar to the individual’s own. These increases were associated with increased activity in the medial prefrontal cortex while participants received social feedback. Furthermore, pretreatment with the 5-HT2A antagonist ketanserin fully blocked LSD-induced changes during feedback processing, indicating a key role of the 5-HT2A system in social feedback processing. Our results highlight the crucial role of the 5-HT-system in social influence and, thus, provide important insight into the neuropharmacological basis of social cognition and behavior.

Duerler, P., Schilbach, L., Stämpfli, P., Vollenweider, F. X., & Preller, K. H. (2020). LSD-induced increases in social adaptation to opinions similar to one’s own are associated with stimulation of serotonin receptors. Scientific reports, 10(1), 12181. https://doi.org/10.1038/s41598-020-68899-y

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LSD-induced increases in social adaptation to opinions similar to one’s own are associated with stimulation of serotonin receptors

Abstract

Adapting one’s attitudes and behaviors to group norms is essential for successful social interaction and, thus, participation in society. Yet, despite its importance for societal and individual functioning, the underlying neuropharmacology is poorly understood. We therefore investigated its neurochemical and neural correlates in a pharmacological functional magnetic resonance imaging study. Lysergic acid diethylamide (LSD) has been shown to alter social processing and therefore provides the unique opportunity to investigate the role of the 5-HT2A receptor in social influence processing. Twenty-four healthy human volunteers received either (1) placebo + placebo, (2) placebo + LSD (100 µg), or (3) the 5-HT2A receptor antagonist ketanserin (40 mg) + LSD (100 µg) at three different occasions in a double-blind, randomized, counterbalanced, cross-over design. LSD increases social adaptation but only if the opinions of others are similar to the individual’s own. These increases were associated with increased activity in the medial prefrontal cortex while participants received social feedback. Furthermore, pretreatment with the 5-HT2A antagonist ketanserin fully blocked LSD-induced changes during feedback processing, indicating a key role of the 5-HT2A system in social feedback processing. Our results highlight the crucial role of the 5-HT-system in social influence and, thus, provide important insight into the neuropharmacological basis of social cognition and behavior.
Duerler, P., Schilbach, L., Stämpfli, P., Vollenweider, F. X., & Preller, K. H. (2020). LSD-induced increases in social adaptation to opinions similar to one’s own are associated with stimulation of serotonin receptors. Scientific reports10(1), 1-11., https://doi.org/10.1038/s41598-020-68899-y
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Serotonergic psychedelics LSD & psilocybin increase the fractal dimension of cortical brain activity in spatial and temporal domains

Abstract

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.

Varley, T. F., Carhart-Harris, R., Roseman, L., Menon, D. K., & Stamatakis, E. A. (2020). Serotonergic psychedelics LSD & psilocybin increase the fractal dimension of cortical brain activity in spatial and temporal domains. NeuroImage, 220, 117049. https://doi.org/10.1016/j.neuroimage.2020.117049

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Serotonergic psychedelics LSD & psilocybin increase the fractal dimension of cortical brain activity in spatial and temporal domains

Abstract

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.

Varley, T. F., Carhart-Harris, R., Roseman, L., Menon, D. K., & Stamatakis, E. A. (2020). Serotonergic psychedelics LSD & psilocybin increase the fractal dimension of cortical brain activity in spatial and temporal domains. NeuroImage220, 117049; 10.1016/j.neuroimage.2020.117049
Link to full text

Serotonergic psychedelics LSD & psilocybin increase the fractal dimension of cortical brain activity in spatial and temporal domains

Abstract

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.

Varley, T. F., Carhart-Harris, R., Roseman, L., Menon, D. K., & Stamatakis, E. A. (2020). Serotonergic psychedelics LSD & psilocybin increase the fractal dimension of cortical brain activity in spatial and temporal domains. NeuroImage220, 117049; 10.1016/j.neuroimage.2020.117049
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Spotlight commentary: REBUS and the anarchic brain

Abstract

In ‘REBUS and the Anarchic Brain: Towards a Unified Model of the Brain Action of Psychedelics’, Carhart-Harris and Friston offer an important analysis of what the predictive processing framework has to offer our understanding of psychedelic experiences, providing an invaluable ground for psychedelic psychiatry. While applauding this, we encourage paying greater attention to contextual factors shaping extreme experiences and their sequalae, and suggest that the authors’ comparisons with certain non-psychedelic altered states may overlook more informative parallels that can be drawn elsewhere. Addressing both points will prove fruitful, ultimately, in identifying the mechanisms of action of greatest interest in psychedelic experiences.
Carhart-Harris, R. L., & Friston, K. J. (2019). REBUS and the anarchic brain: toward a unified model of the brain action of psychedelics. Pharmacological reviews71(3), 316-344., https://doi.org/10.1093/nc/niaa007
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Mystical Experiences in Retrospective Reports of First Times Using a Psychedelic in Finland

Abstract

Despite their acutely inebriating and sometimes unpleasant effects, some people report positive changes in life satisfaction, well-being, or mental health after taking psychedelic drugs. One explanation may be the ability of psychedelics to trigger mystical-type experiences. We examined the validity, reliability, and factor structure of a novel Finnish translation of the Revised Mystical Experiences Questionnaire (MEQ30) among 288 people retrospectively reporting on their first time using a psychedelic. We found evidence for internal consistency reliability and preliminary evidence for criterion and discriminant validity of the Finnish MEQ30. A four-factor structure with factors for mystical qualities, positive mood, transcendence, and ineffability had the best, fair to reasonable fit to the data. MEQ30 scores and having a full mystical experience were highly associated with describing the experience as mystical, spiritual, or religious, and as personally significant, and somewhat associated with the experience being sad or difficult. Mystical experiences were especially associated with positive changes in relationships with nature and oneself and in creativity. Mystical experiences were more common with larger doses. Increasing research suggests mystical-type experiences to relate to positive changes after taking psychedelics. The Finnish MEQ30 is able to tap into relevant information about this aspect of people’s psychedelic experiences.
Kangaslampi, S., Hausen, A., & Rauteenmaa, T. (2020). Mystical Experiences in Retrospective Reports of First Times Using a Psychedelic in Finland. Journal of Psychoactive Drugs, 1-10. https://doi.org/10.1080/02791072.2020.1767321
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Psychedelic treatment of functional neurological disorder: a systematic review

Abstract

Functional neurological disorder (FND), formerly known as conversion disorder, causes a high burden of disability and distress, and is amongst the most commonly encountered conditions in neurology clinics and neuropsychiatric services, yet the therapeutic evidence base is somewhat limited. There has been recent interest in the therapeutic potential of psychedelics such as psilocybin and lysergic acid diethylamide (LSD), and in recent studies psychedelics have shown promise in treating a range of neuropsychiatric conditions. Modification of neural circuits associated with self-representation is thought to underlie some of this effect, and as some contemporary theories of FND focus on aberrant somatic self-representation, psychedelics may therefore represent an unexplored treatment option for FND. We systematically reviewed studies involving the use of psychedelics in FND. Nine studies published between 1954 and 1967, with a total of 26 patients, were identified. Due to restriction of licencing of psychedelic drugs since this period, no modern studies were identified. In most cases, patients received a course of psychotherapy with variable adjunctive administration of psychedelics (in a combination known as ‘psycholytic therapy’), with protocols varying between studies. Of those treated, 69% (n = 18) were found to have made at least some recovery on heterogeneous and subjective clinician-rated criteria. Adverse events were mostly mild and transient; however, at least one patient terminated the study due to distressing effects. All included studies were of low quality, often lacking control groups and valid outcome measures. Although no conclusions on efficacy may be drawn from these data, further research may help to determine whether psychedelics offer a feasible, safe and effective treatment for FND.
Butler, M., Seynaeve, M., Nicholson, T. R., Pick, S., Kanaan, R. A., Lees, A., … & Rucker, J. (2020). Psychedelic treatment of functional neurological disorder: a systematic review. Therapeutic Advances in Psychopharmacology10, 2045125320912125., https://doi.org/10.1177%2F2045125320912125
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Psilocybin and LSD Have No Long-Lasting Effects in an Animal Model of Alcohol Relapse

Abstract

For most psychiatric disorders, including alcohol use disorder (AUD), approved pharmacological treatments are limited in their effectiveness, and new drugs that can easily be translated into the clinic are needed. Currently, great hope lies in the potential of psychedelics to effectively treat AUD. The primary hypothesis is that a single session of psychedelic-guided psychotherapy can restore normal brain function in AUD individuals and thereby reduce the risk of relapse in the long run. Here we applied three different treatment schedules with psilocybin/LSD in order to investigate relapse-like drinking in the alcohol deprivation effect (ADE) model. In contrast to the primary hypothesis, psychedelics had no long-lasting effects on the ADE in male and female rats, neither when administered in a high dosage regime that is comparable to the one used in clinical studies, nor in a chronic microdosing scheme. Only sub-chronic treatment with psilocybin produced a short-lasting anti-relapse effect. However, it is not a translatable treatment option to give psychedelics sub-chronically for relapse prevention. In conclusion, our results in the ADE model do not support the hypothesis that microdosing or high doses of psychedelic reduce relapse behavior. This conclusion has to be confirmed by applying other animal models of AUD. It could also well be that animal models of AUD might be unable to fully capture the therapeutic potential of psychedelic drugs and that only future large-scale clinical trials will be able to demonstrate the efficacy of psychedelics as a new treatment option for AUD.

Meinhardt, M. W., Güngör, C., Skorodumov, I., Mertens, L. J., & Spanagel, R. (2020). Psilocybin and LSD have no long-lasting effects in an animal model of alcohol relapse. Neuropsychopharmacology, 1-9., https://doi.org/10.1038/s41386-020-0694-z
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Chronic pain and psychedelics: a review and proposed mechanism of action

Abstract

The development of chronic pain is a complex mechanism that is still not fully understood. Multiple somatic and visceral afferent pain signals, when experienced over time, cause a strengthening of certain neural circuitry through peripheral and central sensitization, resulting in the physical and emotional perceptual chronic pain experience. The mind-altering qualities of psychedelics have been attributed, through serotonin 2A (5-HT2A) receptor agonism, to ‘reset’ areas of functional connectivity (FC) in the brain that play prominent roles in many central neuropathic states. Psychedelic substances have a generally favorable safety profile, especially when compared with opioid analgesics. Clinical evidence to date for their use for chronic pain is limited; however, several studies and reports over the past 50 years have shown potential analgesic benefit in cancer pain, phantom limb pain and cluster headache. While the mechanisms by which the classic psychedelics may provide analgesia are not clear, several possibilities exist given the similarity between 5-HT2A activation pathways of psychedelics and the nociceptive modulation pathways in humans. Additionally, the alterations in FC seen with psychedelic use suggest a way that these agents could help reverse the changes in neural connections seen in chronic pain states. Given the current state of the opioid epidemic and limited efficacy of non-opioid analgesics, it is time to consider further research on psychedelics as analgesics in order to improve the lives of patients with chronic pain conditions.
Castellanos, J. P., Woolley, C., Bruno, K. A., Zeidan, F., Halberstadt, A., & Furnish, T. (2020). Chronic pain and psychedelics: a review and proposed mechanism of action. Regional Anesthesia & Pain Medicine., http://dx.doi.org/10.1136/rapm-2020-101273
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