Novel cognitive states
A novel cognitive state is defined as any cognitive effect which does not merely amplify or suppress familiar states of mind, but rather induces an experience that is qualitatively different from that of ordinary consciousness.
Although many transpersonal and psychological effects also technically fit into this definition, they are excluded from this category of effects as they have their own defining qualities which standard novel states do not.
This page lists and describes the various novel states which can occur under the influence of certain psychoactive compounds.
Autonomous voice communication
Autonomous voice communication (also known as auditory verbal hallucinations (AVHs)) is defined as the experience of being able to hear and converse with a disembodied and audible voice of unknown origin which seemingly resides within one's own head. This voice is often capable of high levels of complex and detailed speech which are typically on par with the intelligence and vocabulary of ones own conversational abilities.
As a whole, the effect itself can be broken down into 5 distinct levels of progressive intensity, each of which are described below:
- A sensed presence of the other - The distinctive feeling that another form of consciousness is internally present alongside that of one's usual sense of self. This sensation is often referred to within the scientific literature as a "sense of presence".
- Mutually generated internal responses - Internally felt conversational responses to one's own thoughts and feelings which feel as if they are partially generated by one's own thought stream and in equal measure by that of a separate thought stream.
- Separately generated internal responses - Internally felt conversational responses to one's own thoughts and feelings which feel as if they are generated by an entirely distinct and separate thought stream that resides within one's head.
- Separately generated audible internal responses - Internally heard conversational responses to one's own thoughts and feelings which are perceived as a clearly defined and audible voice within one's head. These can take on a variety of voices, accents, and dialects, but usually sound identical to one's own spoken voice.
- Separately generated audible external responses - Externally heard conversational responses to one's own thoughts and feelings which are perceived as a clearly defined and audible voice which sounds as if it is coming from outside one's own head. These can take on a variety of voices, accents, and dialects, but usually sound identical to the person's own spoken voice.
The speaker behind this voice is commonly interpreted by those who experience it to be the voice of their own subconscious, the psychoactive substance itself, a specific autonomous entity, or even supernatural concepts such as god, spirits, souls, and ancestors.
At higher levels, the conversational style of that which is discussed between both the voice and its host can be described as essentially identical in terms of its coherency and linguistic intelligibility as that of any other everyday interaction between the self and another human being of any age with which one might engage in conversation with. Higher levels may also manifest itself in multiple voices or even an ambiguous collection of voices such as a crowd.
However, there are some subtle but identifiable differences between this experience and that of normal everyday conversations. These stem from the fact that one's specific set of knowledge, memories and experiences are identical to that of the voice which is being communicated with. This results in conversations in which both participants often share an identical vocabulary down to the very use of their colloquial slang and subtle mannerisms. As a result of this, no matter how in-depth and detailed the discussion becomes, no entirely new information is ever exchanged between the two communicators. Instead, the discussion focuses primarily on building upon old ideas and discussing new opinions or perspectives regarding the previously established content of one's life.
Autonomous voice communication is often accompanied by other coinciding effects such as delusions, autonomous entities, auditory hallucinations, and psychosis in a manner which can sometimes lead the person into believing the voices' statements unquestionably in a delusional manner. It is most commonly induced under the influence of heavy dosages of hallucinogenic compounds such as psychedelics, dissociatives, and deliriants. However, it may also occur during the offset of prolonged stimulant binges and less consistently under the influence of heavy dosages of cannabinoids.
The experience of communicating with hallucinated voices has been well established with and without the use of hallucinogenic drugs through scientific study. For example, one study successfully demonstrated that anybody can encounter a dialogue between themselves and a voice of unknown origin under the influence of psilocybin mushrooms. This study interviewed 128 participants with an approximate total of 3,427 psilocybin mushroom experiences between them and revealed that 35.9% (46) of the participants reported voices whilst 64% (82) did not.
Even outside of these drug-induced experiences, hearing voices within one's head is a well documented psychological phenomena and can in and of itself, generally be considered as a relatively harmless state of mind to find oneself in.
Cognitive dysphoria (semantically the opposite of euphoria) is medically recognized as a cognitive and emotional state in which a person experiences intense feelings of dissatisfaction, and in some cases indifference to the world around them. These feelings can vary in their intensity depending on the dosage consumed and the user's susceptibility to mental instability. Although dysphoria is an effect, the term is also used colloquially to define a state of general melancholic unhappiness (such as that of mild depression) often combined with an overwhelming sense of discomfort and malaise.
Cognitive dysphoria is often accompanied by other coinciding effects such as anxiety and depression. It is most commonly induced under the influence of moderate dosages of deliriant compounds, such as DPH and datura. However, it can also occur during a stimulant's offset and during the withdrawal symptoms of almost any substance.
Cognitive euphoria (semantically the opposite of cognitive dysphoria) is medically recognized as a cognitive and emotional state in which a person experiences intense feelings of well-being, elation, happiness, excitement, and joy. Although euphoria is an effect (i.e. a substance is euphorigenic), the term is also used colloquially to define a state of transcendent happiness combined with an intense sense of contentment. However, recent psychological research suggests euphoria can largely contribute to but should not be equated with happiness.
Cognitive euphoria is often accompanied by other coinciding effects such as physical euphoria and tactile enhancement. It is most commonly induced under the influence of moderate dosages of opioids, entactogens, stimulants, and GABAergic depressants. However, it can also occur to a lesser extent under the influence of hallucinogenic compounds such as psychedelics, dissociatives, and cannabinoids.
Compulsive redosing is defined as the experience of a powerful and difficult to resist urge to continuously redose a psychoactive substance in an effort to increase or maintain the subjective effects which it induces.
This effect is considerably more likely to manifest itself when the user has a large supply of the given substance within their possession. It can be partially avoided by pre-weighing dosages, not keeping the remaining material within sight, exerting self-control, and giving the compound to a trusted individual to keep until they deem it safe to return.
Compulsive redosing is often accompanied by other coinciding effects such as cognitive euphoria, physical euphoria, or anxiety suppression alongside of other effects which inhibit the clarity of one's decision-making processes such as disinhibition, motivation enhancement, and ego inflation. It is most commonly induced under the influence of moderate dosages of a wide variety of compounds, such as opioids, stimulants, GABAergics, and entactogens. However, it can also occur to a lesser extent under the influence of dissociatives and cannabinoids.
Conceptual thinking is defined as an alteration to the nature and content of one's internal thought stream. This alteration predisposes a user to think thoughts which are no longer primarily comprised of words and linear sentence structures. Instead, thoughts become equally comprised of what is perceived to be incredibly detailed renditions of the innately understandable and internally stored concepts for which no words exist. Thoughts cease to be spoken by an internal narrator and are instead “felt” and intuitively understood.
For example, if a person was to think of an idea such as a "chair" during this state, one would not hear the word as part of an internal thought stream, but would feel the internally stored, pre-linguistic and innately understandable data which comprises the specific concept labelled within one's memory as a "chair". These conceptual thoughts are felt in a comprehensive level of detail that feels as if it is unparalleled within the primarily linguistic thought structure of everyday life. This is sometimes interpreted by those who undergo it as some "higher level of understanding".
During this experience, conceptual thinking can cause one to feel not just the entirety of a concept's attributed data, but also how a given concept relates to and depends upon other known concepts. This can result in the perception that the person can better comprehend the complex interplay between the idea that is being contemplated and how it relates to other ideas.
Conceptual thinking is often accompanied by other coinciding effects such as personal bias suppression and analysis enhancement. It is most commonly induced under the influence of moderate dosages of hallucinogenic compounds, such as psychedelics and dissociatives. However, it can also occur to a lesser extent under the influence of entactogens, cannabinoids, and meditation.
Enhancement and suppression cycles
Enhancement and suppression cycles is defined as an effect which results in two opposite states of mind that do not occur simultaneously but instead swap between each other at seemingly random intervals. These intervals are generally 10-30 minutes in length but can occasionally be considerably shorter.
The first of these two alternate states can be described as the experience of cognitive enhancements which feel is if they drastically improve the person's ability to think clearly. This includes analysis enhancement, thought organization, thought acceleration, creativity enhancement, and thought connectivity.
The second of these two alternate states can be described as the experience of a range of cognitive suppressions which feel as if they drastically inhibit the person's ability to think clearly. These typically include specific effects such as thought deceleration, thought disorganization, creativity suppression, language suppression, and analysis suppression.
Multiple thought streams
Multiple thought streams is defined as a state of mind in which a person has more than one internal narrative or stream of consciousness simultaneously occurring within their head. This can result in any number of independent thought streams occurring at the same time, each of which are often controllable in a similar manner to that of one's everyday thought stream.
These multiple coinciding thought streams can be experienced simultaneously in a manner which is evenly distributed and does not prioritize the awareness of any particular thought stream over an other. However, they can also be experienced in a manner which feels as if it brings awareness of a particular thought stream to the foreground while the others continue processing information in the background. This form of multiple thought streams typically swaps between specific trains of thought at seemingly random intervals.
The experience of this effect can sometimes allow one to analyze many different ideas simultaneously and can be a source of great insight. However, it will usually overwhelm the person with an abundance of information that becomes difficult or impossible to fully process at a normal speed.
Multiple thought streams are often accompanied by other coinciding effects such as memory suppression and thought disorganization. They are most commonly induced under the influence of heavy dosages of psychedelic compounds, such as LSD, psilocybin, and mescaline.
Simultaneous emotions is defined as the experience of feeling multiple emotions simultaneously without an obvious external trigger. For example, during this state a user may suddenly feel intense conflicting emotions such as simultaneous happiness, sadness, love, hate, etc. This can result in states of mind in which the user can potentially feel any number of conflicting emotions in any possible combination.
Simultaneous emotions are often accompanied by other coinciding effects such as memory suppression and emotion enhancement. They are most commonly induced under the influence of heavy dosages of psychedelic compounds, such as LSD, psilocybin, and mescaline.
Spatial disorientation is defined as the failure to perceive or perceiving incorrectly the position, motion, or altitude of oneself within the fixed coordinate system provided by the surface of the Earth and the gravitational vertical. In this state, a person may have trouble distinguishing up from down, right from left, or any two different directions from another. The person might also perceive the world or their own body as being flipped sideways or upside down.
Spatial disorientation is often accompanied by other coinciding effects such as holes, spaces and voids, changes in felt gravity, and dizziness. It is most commonly induced under the influence of moderate dosages of dissociative compounds, such as diphenidine, ketamine, and DXM.
A thought loop is defined as the experience of becoming trapped within a chain of thoughts, actions and emotions which repeats itself over and over again in a cyclic loop. These loops usually range from anywhere between 5 seconds and 2 minutes in length. However, some users have reported them to be up to a few hours in length. It can be extremely disorientating to undergo this effect and it often triggers states of progressive anxiety within people who may be unfamiliar with the experience. The most effective way to end a cycle of thought loops is to simply sit down and try to let go.
This state of mind is most likely to occur during states of memory suppression in which there is a partial or complete failure of the person's short-term memory. This may suggest that thought loops are the result of cognitive processes becoming unable to sustain themselves for appropriate lengths of time due to a lapse in short-term memory, resulting in the thought process attempting to restart from the beginning only to fall short once again in a perpetual cycle.
Thought loops are most commonly induced under the influence of heavy dosages of hallucinogenic compounds, such as psychedelics and dissociatives. However, they can also occur to a lesser extent under the influence of extremely heavy dosages of stimulants and benzodiazepines.
Time distortion is defined as an effect that makes the passage of time feel difficult to keep track of and wildly distorted. It is usually felt in two different forms, time dilation and time compression. These two forms are described and documented below:
Time dilation is defined as the feeling that time has slowed down. This commonly occurs during intense hallucinogenic experiences and seems to stem from the fact that during an intense trip, abnormally large amounts of experience are felt in very short periods of time. This can create the illusion that more time has passed than actually has. For example, at the end of certain experiences, one may feel that they have subjectively undergone days, weeks, months, years, or even infinite periods of time.
Time dilation is often accompanied by other coinciding effects such as spirituality enhancement, thought loops, novelty enhancement, and internal hallucinations in a manner which may lead one into perceiving a disproportionately large number of events considering the amount of time that has actually passed in the real world. It is most commonly induced under the influence of heavy dosages of hallucinogenic compounds, such as psychedelics, dissociatives, entactogens, and cannabinoids.
Time compression is defined as the experience of time speeding up and passing much quicker than it usually would while sober. For example, during this state a person may realize that an entire evening has passed them by in what feels like only a couple of hours.
This commonly occurs under the influence of certain stimulating compounds and seems to at least partially stem from the fact that during intense levels of stimulation, people typically become hyper-focused on activities and tasks in a manner which can allow time to pass them by without realizing it. However, the same experience can also occur on depressant compounds which induce amnesia. This occurs due to the way in which a person can literally forget everything that has happened while still experiencing the effects of the substance, thus giving the impression that they have suddenly jumped forward in time.
Time compression is often accompanied by other coinciding effects such as memory suppression, focus enhancement, stimulation, and amnesia in a manner which may lead one into perceiving a disproportionately small number of events considering the amount of time that has actually passed in the real world. It is most commonly induced under the influence of heavy dosages of stimulating and/or amnesic compounds, such as dissociatives, entactogens, amphetamines, and benzodiazepines.
Time reversal is defined as the perception that the events, hallucinations, and experiences that occurred around one's self within the previous several minutes to several hours are spontaneously playing backwards in a manner which is somewhat similar to that of a rewinding VHS tape. During this reversal, the person's cognition and train of thought will typically continue to play forward in a coherent and linear manner while they watch the external environment around them and their body's physical actions play in reverse order. This can either occur in real time, with 5 minutes of time reversal taking approximately 5 minutes to fully rewind, or it can occur in a manner which is sped up, with 5 minutes of time reversal only taking less than a minute. It can reasonably be speculated that the experience of time reversal may potentially occur through a combination of internal hallucinations and errors in memory encoding.
Time reversal is often accompanied by other coinciding effects such as internal hallucinations, thought loops, and deja vu. It is most commonly induced under the influence of extremely heavy dosages of hallucinogenic compounds, such as psychedelics, dissociatives, and deliriants.
- Toh, Wei Lin; Castle, David J.; Thomas, Neil; Badcock, Johanna C.; Rossell, Susan L. (2016). "Auditory verbal hallucinations (AVHs) and related psychotic phenomena in mood disorders: analysis of the 2010 Survey of High Impact Psychosis (SHIP) data". Psychiatry Research. 243: 238–245. doi:10.1016/j.psychres.2016.06.035. ISSN 0165-1781.
- Moseley, Peter; Fernyhough, Charles; Ellison, Amanda (2013). "Auditory verbal hallucinations as atypical inner speech monitoring, and the potential of neurostimulation as a treatment option". Neuroscience & Biobehavioral Reviews. 37 (10): 2794–2805. doi:10.1016/j.neubiorev.2013.10.001. ISSN 0149-7634.
- Woods, Angela; Jones, Nev; Alderson-Day, Ben; Callard, Felicity; Fernyhough, Charles (2015). "Experiences of hearing voices: analysis of a novel phenomenological survey". The Lancet Psychiatry. 2 (4): 323–331. doi:10.1016/S2215-0366(15)00006-1. ISSN 2215-0366.
- Romme, M. A. J.; Honig, A.; Noorthoorn, E. O.; Escher, A. D. M. A. C. (2018). "Coping with Hearing Voices: An Emancipatory Approach". British Journal of Psychiatry. 161 (01): 99–103. doi:10.1192/bjp.161.1.99. ISSN 0007-1250.
- Corstens, Dirk; Longden, Eleanor; McCarthy-Jones, Simon; Waddingham, Rachel; Thomas, Neil (2014). "Emerging Perspectives From the Hearing Voices Movement: Implications for Research and Practice". Schizophrenia Bulletin. 40 (Suppl_4): S285–S294. doi:10.1093/schbul/sbu007. ISSN 1745-1701.
- Fenelon, G.; Soulas, T.; de Langavant, L. C.; Trinkler, I.; Bachoud-Levi, A.-C. (2011). "Feeling of presence in Parkinson's disease". Journal of Neurology, Neurosurgery & Psychiatry. 82 (11): 1219–1224. doi:10.1136/jnnp.2010.234799. ISSN 0022-3050.
- Hayes, Jacqueline; Leudar, Ivan (2016). "Experiences of continued presence: On the practical consequences of 'hallucinations' in bereavement". Psychology and Psychotherapy: Theory, Research and Practice. 89 (2): 194–210. doi:10.1111/papt.12067. ISSN 1476-0835.
- SherMer, M. (2010). The Sensed-Presence Effect. Scientific American, 302(4), 34. https://www.scientificamerican.com/article/the-sensed-presence-effect/
- Looijestijn, Jasper; Diederen, Kelly M.J.; Goekoop, Rutger; Sommer, Iris E.C.; Daalman, Kirstin; Kahn, René S.; Hoek, Hans W.; Blom, Jan Dirk (2013). "The auditory dorsal stream plays a crucial role in projecting hallucinated voices into external space". Schizophrenia Research. 146 (1-3): 314–319. doi:10.1016/j.schres.2013.02.004. ISSN 0920-9964.
- Beach, H. J. (1997). Listening for the logos: A study of reports of audible voices at high doses of psilocybin. http://www.maps.org/news-letters/v07n1/07112bea.html
- Robertson, Michelle; Toh, Wei Lin (2017). "M109. Phenomenology of Auditory Verbal Hallucinations (AVHs) in a Nonclinical Adult Population and Their Relationship With Mood". Schizophrenia Bulletin. 43 (suppl_1): S250–S250. doi:10.1093/schbul/sbx022.104. ISSN 0586-7614.
- Luhrmann, T. M.; Padmavati, R.; Tharoor, H.; Osei, A. (2018). "Differences in voice-hearing experiences of people with psychosis in the USA, India and Ghana: Interview-based study". British Journal of Psychiatry. 206 (01): 41–44. doi:10.1192/bjp.bp.113.139048. ISSN 0007-1250.
- "Glossary of Technical Terms". Diagnostic and statistical manual of mental disorders (5th ed.): 821. 2013. doi:10.1176/appi.books.9780890425596.GlossaryofTechnicalTerms.
- Zoellner, Lori A.; Pruitt, Larry D.; Farach, Frank J.; Jun, Janie J. (2014). "UNDERSTANDING HETEROGENEITY IN PTSD: FEAR, DYSPHORIA, AND DISTRESS". Depression and Anxiety. 31 (2): 97–106. doi:10.1002/da.22133. ISSN 1091-4269.
- Epkins, Catherine C. (1996). "Cognitive specificity and affective confounding in social anxiety and dysphoria in children". Journal of Psychopathology and Behavioral Assessment. 18 (1): 83–101. doi:10.1007/BF02229104. ISSN 0882-2689.
- Bradley, Brendan P.; Mogg, Karin; Lee, Stacey C. (1997). "Attentional biases for negative information in induced and naturally occurring dysphoria". Behaviour Research and Therapy. 35 (10): 911–927. doi:10.1016/S0005-7967(97)00053-3. ISSN 0005-7967.
- Disner, Seth G.; Beevers, Christopher G.; Haigh, Emily A. P.; Beck, Aaron T. (2011). "Neural mechanisms of the cognitive model of depression". Nature Reviews Neuroscience. 12 (8): 467–477. doi:10.1038/nrn3027. ISSN 1471-003X.
- Koster, Ernst H. W.; De Raedt, Rudi; Goeleven, Ellen; Franck, Erik; Crombez, Geert (2005). "Mood-Congruent Attentional Bias in Dysphoria: Maintained Attention to and Impaired Disengagement From Negative Information". Emotion. 5 (4): 446–455. doi:10.1037/1528-35184.108.40.2066. ISSN 1931-1516.
- "Glossary of Technical Terms". Diagnostic and statistical manual of mental disorders (5th ed.): 821. 2013. doi:10.1176/appi.books.9780890425596.GlossaryofTechnicalTerms.
- Drevets, Wayne C; Gautier, Clara; Price, Julie C; Kupfer, David J; Kinahan, Paul E; Grace, Anthony A; Price, Joseph L; Mathis, Chester A (2001). "Amphetamine-induced dopamine release in human ventral striatum correlates with euphoria". Biological Psychiatry. 49 (2): 81–96. doi:10.1016/S0006-3223(00)01038-6. ISSN 0006-3223.
- Jônsson, Lars-Erik; Änggård, Erik; Gunne, Lars-M (1971). "Blockade of intravenous amphetamine euphoria in man". Clinical Pharmacology & Therapeutics. 12 (6): 889–896. doi:10.1002/cpt1971126889. ISSN 0009-9236.
- Synofzik, Matthis; Schlaepfer, Thomas E.; Fins, Joseph J. (2012). "How Happy Is Too Happy? Euphoria, Neuroethics, and Deep Brain Stimulation of the Nucleus Accumbens". AJOB Neuroscience. 3 (1): 30–36. doi:10.1080/21507740.2011.635633. ISSN 2150-7740.
- Lucas, Richard E.; Diener, Ed; Suh, Eunkook (1996). "Discriminant validity of well-being measures". Journal of Personality and Social Psychology. 71 (3): 616–628. doi:10.1037/0022-35220.127.116.116. ISSN 1939-1315.
- Everitt, Barry J; Robbins, Trevor W (2005). "Neural systems of reinforcement for drug addiction: from actions to habits to compulsion". Nature Neuroscience. 8 (11): 1481–1489. doi:10.1038/nn1579. ISSN 1097-6256.
- Volkow, N. D. (2000). "Addiction, a Disease of Compulsion and Drive: Involvement of the Orbitofrontal Cortex". Cerebral Cortex. 10 (3): 318–325. doi:10.1093/cercor/10.3.318. ISSN 1460-2199.
- Hyman, Steven E.; Malenka, Robert C. (2001). "Addiction and the brain: The neurobiology of compulsion and its persistence". Nature Reviews Neuroscience. 2 (10): 695–703. doi:10.1038/35094560. ISSN 1471-003X.
- Soussan, Christophe; Kjellgren, Anette (2015). ""Chasing the High" – Experiences of Ethylphenidate as Described on International Internet Forums". Substance Abuse: Research and Treatment. 9: SART.S22495. doi:10.4137/SART.S22495. ISSN 1178-2218.
- Olives, Travis; Orozco, Benjamin; Stellpflug, Samuel (2012). "Bath Salts: The Ivory Wave of Trouble". Western Journal of Emergency Medicine. 13 (1): 58–62. doi:10.5811/westjem.2011.6.6782. ISSN 1936-900X.
- Peters, R. A. (1969). Dynamics of the vestibular system and their relation to motion perception, spatial disorientation, and illusions. https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19690013275.pdf
- Cheung, Bob (2013). "Spatial Disorientation: More Than Just Illusion". Aviation, Space, and Environmental Medicine. 84 (11): 1211–1214. doi:10.3357/ASEM.3657.2013. ISSN 0095-6562.
- Espiard, M; Lecardeur, L; Abadie, P; Halbecq, I; Dollfus, S (2005). "Hallucinogen persisting perception disorder after psilocybin consumption: a case study". European Psychiatry. 20 (5-6): 458–460. doi:10.1016/j.eurpsy.2005.04.008. ISSN 0924-9338.
- Katselou, Maria; Papoutsis, Ioannis; Nikolaou, Panagiota; Misailidi, Nektaria; Spiliopoulou, Chara; Athanaselis, Sotiris (2018). "Diphenidine: a dissociative NPS makes an entrance on the drug scene". Forensic Toxicology. 36 (2): 233–242. doi:10.1007/s11419-018-0421-1. ISSN 1860-8965.
- Bianchi, Antonio (1997). "Comments on "The Ketamine Model of the Near-Death Experience: A Central Role for the N-Methyl-D-Aspartate Receptor"". Journal of Near-Death Studies. 16 (1): 71–78. doi:10.1023/A:1025067412205. ISSN 0891-4494.
- Bersani, Francesco Saverio; Corazza, Ornella; Albano, Gabriella; Valeriani, Giuseppe; Santacroce, Rita; Bolzan Mariotti Posocco, Flaminia; Cinosi, Eduardo; Simonato, Pierluigi; Martinotti, Giovanni; Bersani, Giuseppe; Schifano, Fabrizio (2014). "25C-NBOMe: Preliminary Data on Pharmacology, Psychoactive Effects, and Toxicity of a New Potent and Dangerous Hallucinogenic Drug". BioMed Research International. 2014: 1–6. doi:10.1155/2014/734749. ISSN 2314-6133.
- N Stanciu, C., & M Penders, T. (2016). Hallucinogen Persistent Perception Disorder Induced by New Psychoactive Substituted Phenethylamines; A Review with Illustrative Case. Current Psychiatry Reviews, 12(2), 221-223. http://www.ingentaconnect.com/contentone/ben/cpsr/2016/00000012/00000002/art00013
- Nichols, D. E. (2016). "Psychedelics". Pharmacological Reviews. 68 (2): 264–355. doi:10.1124/pr.115.011478. ISSN 1521-0081.
- Pink-Hashkes, S., van Rooij, I., & Kwisthout, J. (2017). Perception is in the details: a predictive coding account of the psychedelic phenomenon. In Proceedings of the 39th Annual Meeting of the Cognitive Science Society (pp. 2907-2912). http://hdl.handle.net/2066/179969
- Hill, R. M.; Fischer, R.; Warshay, Diana (1969). "Effects of excitatory and tranquilizing drugs on visual perception. spatial distortion thresholds". Experientia. 25 (2): 171–172. doi:10.1007/BF01899105. ISSN 0014-4754.
- Fischer, R. (1971). "A Cartography of the Ecstatic and Meditative States". Science. 174 (4012): 897–904. doi:10.1126/science.174.4012.897. ISSN 0036-8075.
- Zalta, E. N. (Ed.). (2003). Stanford encyclopedia of philosophy. http://ruccs.rutgers.edu/images/personal-zenon-pylyshyn/class-info/Consciousness_2014/StanfordEncyclopedia/consciousness-temporal_sc.pdf
- Buckley, P. (1981). "Mystical Experience and Schizophrenia". Schizophrenia Bulletin. 7 (3): 516–521. doi:10.1093/schbul/7.3.516. ISSN 0586-7614.
- Schroll, M. A. (2013). From ecopsychology to transpersonal ecosophy: Shamanism, psychedelics and transpersonal psychology. European Journal of Ecopsychology, 4, 116-144. https://maps.org/news-letters/v19n1/v19n1-pg41.pdf
- Riley, Sarah C.E.; Blackman, Graham (2009). "Between Prohibitions: Patterns and Meanings of Magic Mushroom Use in the UK". Substance Use & Misuse. 43 (1): 55–71. doi:10.1080/10826080701772363. ISSN 1082-6084.
- Nikolova, I.; Danchev, N. (2014). "Piperazine Based Substances of Abuse: A new Party Pills on Bulgarian Drug Market". Biotechnology & Biotechnological Equipment. 22 (2): 652–655. doi:10.1080/13102818.2008.10817529. ISSN 1310-2818.
- Yeap, C. W., Bian, C. K., & Abdullah, A. F. L. (2010). A review on benzylpiperazine and trifluoromethylphenypiperazine: origins, effects, prevalence and legal status. Health Environ J, 1(2), 38-50. http://www.hej.kk.usm.my/pdf/HEJVol.1No.2/Article06.pdf
- Griffith, John D.; Nutt, John G.; Jasinski, Donald R. (1975). "A comparison of fenfluramine and amphetamine in man". Clinical Pharmacology & Therapeutics. 18 (5part1): 563–570. doi:10.1002/cpt1975185part1563. ISSN 0009-9236.
- Corazza, Ornella; Assi, Sulaf; Schifano, Fabrizio (2013). "From "Special K" to "Special M": The Evolution of the Recreational Use of Ketamine and Methoxetamine". CNS Neuroscience & Therapeutics. 19 (6): 454–460. doi:10.1111/cns.12063. ISSN 1755-5930.