Psychedelics and disorders of consciousness: the current landscape and the path forward (original) (raw)
Related papers
Pattern Breaking: A Complex Systems Approach to Psychedelic Medicine
Recent research has demonstrated the potential of psychedelic therapy for mental healthcare. However, the psychological experience underlying its therapeutic effects remain poorlyunderstood. This paper proposes a framework that suggests psychedelics act as destabilisers,both psychologically and neurophysiologically. Drawing on the "entropic brain" hypothesisand the "RElaxed Beliefs Under pSychedelics" (REBUS) model, this paper focuses onthe richness of psychological experience. Through a complex systems theory perspective,we suggest that psychedelics destabilize fixed points or attractors, breaking reinforced patternsof thinking and behaving. Our approach explains how psychedelic-induced increases inbrain entropy destabilize neurophysiological set-points and leads to new conceptualizationsof psychedelic psychotherapy. These insights have important implications for risk mitigationand treatment optimization in psychedelic medicine, both during the peak psychedelice...
Ethan Richey, 2020
Throughout history and up to today, the use of medicines to improve health has been a widespread practice amongst many cultures and people. These medicines or healing components include animal parts, plants, pills, and brews, which have been the various methods of treating one’s health. When one thinks of health issues, they typically picture someone who is physically hurt, such as a broken bone or a torn muscle. But in today’s world, health means a lot more than on a physical level. With the increase in cases of people who are clinically diagnosed with depression, anxiety, and other psychological issues, mental health has become a large topic of discussion. Psychologists and people alike have some knowledge in regards to treatment for these diagnoses, but traditional treatment is not enough in most cases. There has been research performed on humans, particularly those who suffer from mental health problems, since the 1950s that involves the ingestion of certain psychedelics, and most of the results turn out positive, with many patients reporting having lost most of their mental disorder symptoms. A key question in the field of psychedelic medicine has been whether or not psychedelics promote positive mental health, but why and how these chemicals produce such behaviors.
Default Mode Network Modulation by Psychedelics: A Systematic Review
International Journal of Neuropsychopharmacology
Psychedelics are a unique class of drug that commonly produce vivid hallucinations as well as profound psychological and mystical experiences. A grouping of interconnected brain regions characterized by increased temporal coherence at rest have been termed the Default Mode Network (DMN). The DMN has been the focus of numerous studies assessing its role in self-referencing, mind wandering, and autobiographical memories. Altered connectivity in the DMN has been associated with a range of neuropsychiatric conditions such as depression, anxiety, post-traumatic stress disorder, attention deficit hyperactive disorder, schizophrenia, and obsessive-compulsive disorder. To date, several studies have investigated how psychedelics modulate this network, but no comprehensive review, to our knowledge, has critically evaluated how major classical psychedelic agents—lysergic acid diethylamide, psilocybin, and ayahuasca—modulate the DMN. Here we present a systematic review of the knowledge base. Ac...
Psychedelics and Consciousness: Distinctions, Demarcations, and Opportunities
International Journal of Neuropsychopharmacology, 2021
Psychedelic substances produce unusual and compelling changes in conscious experience that have prompted some to propose that psychedelics may provide unique insights explaining the nature of consciousness. At present, psychedelics, like other current scientific tools and methods, seem unlikely to provide information relevant to the so-called "hard problem of consciousness," which involves explaining how first-person experience can emerge. However, psychedelics bear on multiple "easy problems of consciousness," which involve relations between subjectivity, brain function, and behavior. In this review, we discuss common meanings of the term "consciousness" when used with regard to psychedelics and consider some models of the effects of psychedelics on the brain that have also been associated with explanatory claims about consciousness. We conclude by calling for epistemic humility regarding the potential for psychedelic research to aid in explaining the hard problem of consciousness while pointing to ways in which psychedelics may advance the study of many specific aspects of consciousness.
Nature Communications, 2022
Psychedelics including lysergic acid diethylamide (LSD) and psilocybin temporarily alter subjective experience through their neurochemical effects. Serotonin 2a (5-HT2a) receptor agonism by these compounds is associated with more diverse (entropic) brain activity. We postulate that this increase in entropy may arise in part from a flattening of the brain's control energy landscape, which can be observed using network control theory to quantify the energy required to transition between recurrent brain states. Using brain states derived from existing functional magnetic resonance imaging (fMRI) datasets, we show that LSD and psilocybin reduce control energy required for brain state transitions compared to placebo. Furthermore, across individuals, reduction in control energy correlates with more frequent state transitions and increased entropy of brain state dynamics. Through network control analysis that incorporates the spatial distribution of 5-HT2a receptors (obtained from publicly available positron emission tomography (PET) data under non-drug conditions), we demonstrate an association between the 5-HT2a receptor and reduced control energy. Our findings provide evidence that 5-HT2a receptor agonist compounds allow for more facile state transitions and more temporally diverse brain activity. More broadly, we demonstrate that receptor-informed network control theory can model the impact of neuropharmacological manipulation on brain activity dynamics. Serotonergic psychedelics like lysergic acid diethylamide (LSD) and psilocybin induce a profound but temporary alteration of perception and subjective experience 1. Combined with non-invasive neuroimaging such as functional MRI, these drugs offer a unique window into the function of the human mind and brain, making it possible to relate mental phenomena to their neural underpinnings. A decade of neuroimaging studies has informed novel insights regarding psychedelic action in the brain 2. One model, known as RElaxed Beliefs Under Psychedelics (REBUS) 3 , integrates previous accounts of psychedelic action (the Entropic Brain Hypothesis) 4,5 with the view of the brain as a prediction engine, whereby perception and belief are shaped by both prior knowledge and incoming information. The REBUS model postulates that psychedelics alter conscious experience via their agonist action at serotonin 2a (5-HT2a) receptors, which have especially high expression in higher-order cortical regions. Agonist-induced dysregulation of spontaneous activity in these regions is postulated to translate into decreased precision-weighting on prior beliefs-which has reciprocal (enabling) implications for bottom-up information flow. It is theorized that the observed increase in entropy of brain activity under psychedelics is reflective of reduced
Restructuring consciousness –the psychedelic state in light of integrated information theory
The psychological state elicited by the classic psychedelics drugs, such as LSD and psilocybin, is one of the most fascinating and yet least understood states of consciousness. However, with the advent of modern functional neuroimaging techniques, the effect of these drugs on neural activity is now being revealed, although many of the varied phenomenological features of the psychedelic state remain challenging to explain. Integrated information theory (IIT) is one of the foremost contemporary theories of consciousness, providing a mathematical formalization of both the quantity and quality of conscious experience. This theory can be applied to all known states of consciousness, including the psychedelic state. Using the results of functional neuroimaging data on the psychedelic state, the effects of psychedelic drugs on both the level and structure of consciousness can be explained in terms of the conceptual framework of IIT. This new IIT-based model of the psychedelic state provides an explanation for many of its phenomenological features, including unconstrained cognition, alterations in the structure and meaning of concepts and a sense of expanded awareness. This model also suggests that whilst cognitive flexibility, creativity, and imagination are enhanced during the psychedelic state, this occurs at the expense of cause-effect information, as well as degrading the brain's ability to organize, categorize, and differentiate the constituents of conscious experience. Furthermore, the model generates specific predictions that can be tested using a combination of functional imaging techniques, as has been applied to the study of levels of consciousness during anesthesia and following brain injury.
Restructuring consciousness –the psychedelic state in light of integrated information theory
Frontiers in Human Neuroscience, 2015
The psychological state elicited by the classic psychedelics drugs, such as LSD and psilocybin, is one of the most fascinating and yet least understood states of consciousness. However, with the advent of modern functional neuroimaging techniques, the effect of these drugs on neural activity is now being revealed, although many of the varied phenomenological features of the psychedelic state remain challenging to explain. Integrated information theory (IIT) is one of the foremost contemporary theories of consciousness, providing a mathematical formalization of both the quantity and quality of conscious experience. This theory can be applied to all known states of consciousness, including the psychedelic state. Using the results of functional neuroimaging data on the psychedelic state, the effects of psychedelic drugs on both the level and structure of consciousness can be explained in terms of the conceptual framework of IIT. This new IIT-based model of the psychedelic state provides an explanation for many of its phenomenological features, including unconstrained cognition, alterations in the structure and meaning of concepts and a sense of expanded awareness. This model also suggests that whilst cognitive flexibility, creativity, and imagination are enhanced during the psychedelic state, this occurs at the expense of cause-effect information, as well as degrading the brain's ability to organize, categorize, and differentiate the constituents of conscious experience. Furthermore, the model generates specific predictions that can be tested using a combination of functional imaging techniques, as has been applied to the study of levels of consciousness during anesthesia and following brain injury.