Here I collect books and articles related to the psychedelic experience (and psychonautics in a broader sense) that I have read or plan to read at some point. Within each section, the entries are listed in descending order with the ones I have most recently read on top. For all entries, I try to give a short summary or review, and highlight ideas or results that I found useful or interesting.
This page also serves as a bookmark list for myself, and others are welcome to make suggestions or discuss topics.
The Psychedelic Experience: A Manual Based on the Tibetan Book of the Dead
- The Psychedelic Experience: A Manual Based on the Tibetan Book of the Dead, T. Leary & R. Alpert (1964)
Based on ancient passing rites that relate closely to the psychedelic experience, this book draws many connections between Buddhist mythology and modern psychology. It describes core concepts of psychonautics such as ego-loss and tries to prepare readers for their own experiences.
The Doors of Perception & Heaven and Hell
- The Doors of Perception & Heaven and Hell, A. Huxley (1956)
Huxley gives an excellent description of the psychedelic experience regarding Mescaline and describes how in ancient times, humans may have been more perceptible to such experiences since they would find easier visual and auditory stimulation. He investigates numerous cultures and religious frameworks to underline this view.
- Cosmos, C. Sagan (1980) gr:55030
- True Hallucinations, T. McKenna (1993) gr:114867
- The Book On the Taboo Against Knowing Who You Are, A.W. Watts (1969) gr:60551
- The Psychedelic Explorer's Guide: Safe, Therapeutic and Sacred Journeys, J. Fadiman (2011) gr:9721527
- Postponend: I found this book to be less of a guide, but more of a collection of scientific investigations. Hence the title is a bit misleading in my opinion, but the book is quite extensive on its own and gives a good overview of scientific research in the psychedelic sector.
- Exploring the World of Lucid Dreaming, S. LaBerge & H. Rheingold (1990) gr:316781
- Postponend: Will be continued at a later time.
Noted for later
- The Fabric of Reality: The Science of Parallel Universes and Its Implications, D. Deutsch (1998) gr:177068
- The Hidden Reality: Parallel Universes and the Deep Laws of the Cosmos, B. Greene (2011) gr:8167094
- LSD: My Problem Childe, A. Hofmann (1979) gr:8791
- Gödel, Escher, Bach: An Eternal Golden Braid, D. Hofstadter (1999) gr:24113
- Decomposing The Shadow: Lessons from the Psilocybin Mushroom, J.W. Jesso (2013), gr:18145374
- The True Light of Darkness, J.W. Jesso (2015) gr:25831302
- The Invisible Landscape, D. & T. McKenna (1994) gr:191375
- Articulations: On the Utilisation and Meanings of Psychedelics, J. Palmer (2014) gr:23857204
- Pihkal: A Chemical Love Story, A. & A. Shulgin (1990) gr:886113
- Tihkal: The Continuation, A. & A. Shulgin (1997) gr:271921
- DMT: The Spirit Molecule, R. Strassmann (2000) gr:51654
- Become What You Are, A.W. & M. Watts (1955) gr:60553
- Out of Your Mind, A.W. Watts (1998) gr:60545
The entropic brain: a theory of conscious states informed by neuroimaging research with psychedelic drugs
- The entropic brain: a theory of conscious states informed by neuroimaging research with psychedelic drugs, R.L. Carhart-Harris et al., Frontiers in Human Neuroscience (8), 2014
- doi:10.3389/fnhum.2014.00020 (OpenAccess)
This article follows a mechanistic approach to neurodynamics and established a concept of two fundamentally different states of consciousness, primary and secondary. While secondary consciousness is linked to normal waking consciousness, which is governed by the default-mode network (DMN) that acts as a conductor to other brain regions, primary consciousness is believed to relate to psychedelic experiences, dreaming, and other typical states of altered consciousness. The paper discusses an assumed reduction in system entropy, which allows the brain to endeavor in unconstrained, explorative thinking which is characteristic of the psychedelic state. It is argued that this is due to psychedelics temporarily disintegrating hierarchical structures in the brain (such as the DMN), which have evolved in humans to allow the construction of an accurate model of the external world to minimize surprise and uncertainty. The sense of ego-loss that is often experienced with psychedelics is linked to the DMN being the physical counterpart of the ego, and a transition into a primary state would relinquish the ego's usual hold on reality.
- Entropy is applied here in the context of states of consciousness [... with a] focus on the psychedelic state [... as] an exemplar of a primitive or primary state [... The] defining feature of "primary states" is elevated entropy [... Entropy] is suppressed in normal waking consciousness [... and] this entropy suppression furnishes normal waking consciousness with a constrained quality and [its] associated metacognitive functions, including reality-testing and self-awareness.
- System entropy, as it is applied to the brain, is related to [...] "self-organized criticality" [... that] refers to how a complex system [...] begins to exhibit interesting properties once it reaches a critical point in a relatively narrow transition zone between the two extremes of order and chaos. [...] There is growing evidence that brain activity, like much of nature, displays critical behavior [...]
- Secondary consciousness
- [...] there must have been a phase-transition in the evolution of human consciousness with the relatively rapid development of the ego and its capacity for metacognition. [... ] the formation of a mature ego endows the mind with a capacity for metacognition i.e., an ability to reflect on one's own thoughts and behavior. [...] the mind has evolved [...] to process the environment as precisely as possible [...] so that surprise and uncertainty (i.e., entropy) are minimized. [...] Secondary consciousness actually depends on the human brain having developed-evolved a degree of sub-criticality [...] this entropy-suppressing function of the brain serves to promote realism, foresight, careful reflection and an ability to overcome wishful and paranoid fantasies [... but] it could be seen as exerting a limiting or narrowing influence on consciousness. [... It] pays deference to reality by carefully sampling the world and learning from its encounters.
- Primary consciousness
- [...] states such as the psychedelic state, REM sleep, the onset-phase of psychosis and the dreamy-state of temporal lobe epilepsy are examples of a regressive style of cognition that is qualitatively different to the normal waking consciousness [... and] we will refer to this mode of cognition as "primary consciousness" [... Freud] argued that dreaming and psychosis typify a primitive style of thinking that is dominant in human infancy and dominated the cognition of primordial man. [...] in primary states, cognition is less meticulous in its sampling of the external world and is instead easily biased by emotion, i.e. wishes and axieties. [...] Primary consciousness may be a sub-optimal mode of cognition that has been superseded by a more reality-bound style of thinking, governed by the ego.
- Default Mode Network
- The magnitude of the DMN's energy consumption dwarfs the comparatively trivial energy changes induced by stimulus cues. DMN regions [...] serve as important connector hubs for information integration and routing. [... The DMN] serves as a central orchestrator or conductor of global brain function [... and is] engaged during higher-level, metacognitive operations such as self-reflection, theory-of-mind and mental time-travel -- functions which may be exclusive to humans. [... The] apparent excess energy of unknown function, residing in the DMN, is in fact the physical counterpart of the narrative-self or ego [...] the coupling between the MTLs and [...] the DMN is necessary for the maintenance of adult normal waking consciousness, with its capacity for metacognition. [...] a breakdown in [this] coupling is necessary for a regression to primary consciousness. [...] coupling within the DMN, and especially between the MTL and the DMN, is [...] necessary for secondary consciousness and the development of an integrated sense of self [... whereas] decreased MTL-DMN coupling allows the MTLs to function more independently of the DMN [... The unconstrained] MTL activity is a principal characteristic of primary states [...] DMN resting-state functionality correlates positively with ratings of internal awareness and trait neuroticism [... and] is reliably elevated in depression [... ] The DMN appears to have a consistently high level of activity [even when it] is relatively deactivated during goal-directed cognition [...]
- By definition, all classic psychedelic drugs are agonists at the serotonin 2A receptor (5-HT2AR) [...] In humans, the distribution of 5-HT2AR [...] is densest in high-level association regions such as the PCC and lowest in the primary motor cortex. [...] 5-HT2AR stimulation depolarizes the host cell, making it more likely to fire [... We found] a highly significant positive correlation between the magnitude of [alpha oscillation's] power decreases in the PCC after psilocybin and ratings of the item "I experienced a disintegration of my 'self' or 'ego'. [...] psychedelics induce a primitive state of consciousness, i.e. "primary consciousness" by relinquishing the ego's usual hold on reality (DMN control on MTL activity). [...] inverse coupling between the DMN and TPNs is decreased under psilocybin, and DMN activity and connectivity is also decreased. [...] unconstrained, explorative thinking is a hallmark of the psychedelic state. [...] it's the ability of psychedelics to disrupt stereotyped patterns of thought and behavior by disintegrating the patterns of activity upon which they rest [...] psychedelics could be used to enhance well-being and divergent thinking [... but also lead to] neglect of accurate reality-testing. [...] psychedelic drugs are especially useful tools for studying primary states as they allow for primary consciousness to be "switched on" with a relatively high degree of experimental control [...]
- Entropic brain
- '[...] unconstrained, explorative thinking is a hallmark of the psychedelic state. There is an emerging view in cognitive neuroscience that the brain self-organizes under normal conditions into transiently stable spatiotemporal configurations [...] activity in higher-level networks becomes relatively disorganized under psilocybin, consistent with the entropic brain hypothesis. [...] increased entropy was observed in [...] the high-level association networks. [...] brain activity is slightly sub-critical in normal waking consciousness [...] it may be advantageous [... for] suppressing endogenous processes within the brain or interacting with the environment to shape and thereby control it. [...] psychedelics work to lower regression and facilitate access to the psychoanalytic unconscious [... which] may relate to the brain moving out of a sub-critical mode of functioning and into a critical one [...] because of the breakdown of the system's hierarchical structure. [... Such changes] may explain the sense of confusion and uncertainty that accompanies a transition from secondary to primary consciousness [... where] confidence is lost in "how the world is" and "who one is" as a personality.
- 'Scientific research with psychedelic drugs can have a revitalizing effect on psychoanalysis [...] we have adopted a mechanistic approach [... and propose] two fundamentally different modes of cognition: primary and secondary consciousness. Primary consciousness is associated with unconstrained cognition and less ordered (higher-entropy) neurodynamics, whereas secondary consciousness is associated with constrained cognition and more ordered neurodynamics. [...] A more thorough discussion of the phenomenology of primary states is required [... to link them] with Freudian accounts of "the unconscious" or "Id." [...] The unique scientific value of psychedelics rests in their capacity to make consciously accessible that which is latent in the mind.
Development of a rational scale to assess the harm of drugs of potential misuse
- Development of a rational scale to assess the harm of drugs of potential misuse, D. Nutt et al., The Lancet (369), 2007
The paper aims at deriving a new assessment scale for the harm of typically misused drugs, including legal ones such as alcohol or tobacco. The study employs a ranking system based on three groups of harm with three subcategories each, and ranks a total of 20 substances in two assessments. The findings highlight that the current classification (class A/B/C in the UK) is essentially arbitrary and not supported by a scientific perspective, especially this is the case for psychedelic compounds. This result likely applies also to similar classification systems, such as schedule I/II/III in the US or BtMG I/II/III in Germany.
- [The] methodology and processes underlying classification systems are generally neither specified or transparent. [...] The ranking of drugs produced by our assessment of harm differed from those used by current regulatory systems.
- Ranking system
- [There are] three main factors that [...] determine the harm associated with any drug of potential abuse: [...] the prospensity of a drug to cause physical harm [...] the pleasurable effects of the drug and its prospensity to produce dependent beahviour [...] harm [to] society in several ways. [... The] route of administration is also relevant to the assessment of harm. [...] Three separate facets of harm can be identified. [...] acute physical harm [...] chronic physical harm [...] specific problems associated with intravenuous drug use.
- Drug dependence
- An essential feature of drugs of abuse is that they encourage repeated use. [...] in the case of hallucinogens [...] it might be the only factor that drives regular use, and such drugs are mostly used infrequently. [...] Physical dependence or addiction involves increasing tolerance [...] intense craving, and withdrawal reactions. [...] Psychological dependence is also characterised by repeated use of a drug, but without tolerance or physical symptoms [...] cannabis can lead to measurable withdrawal symptoms, but only several days after stopping long-standing use.
- [This assessment uses] nine parameters of risk, created by dividing each of the three major categories of harm into three subgroups [... and applies] a four-point scale, with 0 being no risk, 1 some, 2 moderate, and 3 extreme risk. [...] Two independent groups of experts were asked to do the rantings.'
- Replies [from the first group] were received [...] from 29 of the 77 registered [psychiatric] doctors [assessing] 14 compounds -- heroin, cocaine, alcohol, barbiturates, amphetamine, methadone, benzodiazepines, solvents, buprenorphine, tobacco, ecstasy, cannabis, LSD, and steroids. [... The second group] covered the 14 substances [...] plus, for completeness, six other compounds (khat, 4-methylthioamphetamine [4-MTA], gamma 4-hydroxybutric acis [GHB], ketamine, methylphenidate, and alkyl nitrites)
- 'Alcohol, ketamine, tobacco, and solvents [...] were ranked more harmful than LSD, ecstasy and its variant 4-MTA [...] Of the unclassified drugs, alcohol and ketamine were given especially high ratings. Heroin, cocaine, barbiturates, and street methadone were in the top five places for all categories of harm, whereas khat, alkyl nitrites, and ecstasy were in the bottom five places for all. [...] cannabis was ranked low for physical harm but somewhat higher for physical dependence and harm to family and community. [...] Drugs that can be administered by the intravenous system were generally ranked high [...]
- 'The results of this study do not provide justification for the sharp A, B, or C divisions of the current classifications in the UK Misuse of Drugs Act. [...] neither the rank ordering of drugs nor their segregation [...] is supported by the [...] assessment of harm described here. [...] Our findings rais questions about the validity of the current Misuse of Drugs Act classification [...] The discrepancies [...] are especially striking in relation to psychedelic-type drugs.
Homological scaffolds of brain functional networks
- Homological scaffolds of brain functional networks, G. Petri et al., Journal of The Royal Society Interface (11), 2014
- doi:10.1098/rsif.2014.0873 (OpenAccess)
TODO: Highlights to follow soon...
Noted for later
- Complex brain networks: graph theoretical analysis of structural and functional systems, E. Bullmore, Nature Reviews Neuroscience 10, 2009 doi:10.1038/nrn2575
- Psilocybin for treatment-resistant depression: fMRI-measured brain mechanisms, R.L. Carhart-Harris et al., Scientific Reports 7, 2017 doi:10.1038/s41598-017-13282-7 (OpenAccess)
- Psychedelics, D.E. Nichols, Pharmacological Reviews 68 (2), 2016 doi:10.1124/pr.115.011478