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Psychedelics, altered consciousness, and personal growth:
How can psychedelic altered consciousness facilitate personal growth?

Overview

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Psychedelic drugs have always been a controversy in the medicinal field. As we progress further into the 21st century, there has been a paradigm shift within the psychopharmacological community towards the use of psychedelics for therapy.

The etymology of the word 'psychedelic' comes from "psyche", which means "mind"; and "delic", which means "revealing or manifesting". Hence 'psychedelic' translates into "mind-revealing" or "mind-manifesting". The neurochemistry of these drugs are intricate and yet largely undiscovered, considering the immense mind-altering and significantly life-changing properties possessed by them.

Personal Growth Initiative is defined as the intentional and active desire to grow in areas that are salient for a person and is divided into four factors: readiness for change, planfulness (the ability to plan a specific change process), using resources, and intentional behaviour (Engaging in behaviours that facilitate the growth process) (Weigold et al., 2013). We shall explore how psychedelics can facilitate the development of each of these facets of growth.

Focus questions:

  • How do psychedelics work?
  • How does psychedelic-assisted therapy help explore our consciousness?
  • How can we grow through experiencing altered states of consciousness?

Stoned ape theory

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Entheogenic origins of consciousness

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Fig 1. The evolution of the brain from apes to humans

Terrence McKenna, one of the earliest and most influential psychedelic researchers postulated that the evolution of the archaic man (Homo erectus) to the modern man (Homo sapiens) was catalysed by the consumption of entheogenic substances such as psilocybin (Stropharia cubensisic) due to scarcity of food in the Pleistocene era (Richerson et al., 2001). Psilocybin is recognised as an entheogen, which includes psychoactive substances that alter perception, mood, cognition, and consciousness. (Huxtable, R. J., 1992).

The most significant development within the human brain was proposed to be language acquisition (Kuhl, 2010). The expansion of vocabulary and memory capacity had beneficial epigenetic consequences for future generations, as psilocybin-using individuals evolved to survive and reproduce better than other individuals (Lopez, N., 2020).

This concept is further perpetuated by other Indigenous and ancient cultures around the world, as developing a higher level of consciousness is closely linked to the ingestion of hallucinogenic substances during their traditional ceremonies (Rätsch, 2005). Increased doses of psilocybin are correlated to the growth and integration of an individual into a more collective consciousness, enhancing their sense of connectedness to the community (Kettner et al., 2021; Wattes et al., 2017). This is what is known as entheogenesis - "...experiencing and recognising the divine inner source of all beings, both human and nonhuman, both microcosmic and macrocosmic." (Ralph. M., 2017).

Criticism

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In opposition to McKenna's stoped ape theory, Carhart-Harris (2014) discovered that psilocybin inhibits the activity in the prefrontal lobes, rather than enhancing it. He repudiates that the enlargement of the brain was related to the ingestion of psilocybin. Additionally, there is no empirical evidence to support McKenna's claim of increased visual acuity or evidence that Psilocybin cubensis mushrooms were found in the sub-Saharan desert (Helvenston, P. A., 2015).

Entropic brain hypothesis:

Primary process consciousness is a state of mind that occurs when there is no entropy suppression. This means that the brain is in a more disordered and chaotic state, also known as a hyperassociative state, which is usually highly visual in nature. Psychedelics disrupt the default mode network functioning and shift the brain from a more ordered, rational, and analytical state of secondary consciousness to the primary process consciousness. This leads us to explore the increased neural connectivity observed by fMRI scans under the influence of psilocybin.

Psilocybin

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Fig 2. Psilocybe yungensis

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What is it?

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Psilocybe cubensis, colloquially known as "magic mushrooms", are a variety of fungi that are consumed for their intense psychotropic and hallucinatory effects. They contain an active compound, psilocybin, which has potent and often times, long-term effects on an individual's state of consciousness, mindset, and metacognition.[factual?]

Mechanism

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Psilocybin is converted to psilocin (4-Hydroxy-N,N-dimethyltryptamine), an active metabolite (Dinis-Oliveira, R. J., 2017).

It had initially been found that psilocin interrupted the functioning of the default mode network (DMN), which is a group of three brain regions; namely the medial prefrontal cortex, posterior cingulate cortex, and angular gyrus (Carhart-Harris et. al, 2012). These cortical regions are densely packed with 5HT2A (serotonin) receptors and produce altered states of consciousness that involve feelings of "connectedness" to one's environment. However, further research uncovered that only certain subsets of the DMN are related to the phenomenology of these psychedelic experiences, which is inconsistent with the previous hypotheses (Varley, T. et al., 2020).

Overall, a revision of the entropic brain hypothesis ascribes the function of relaxing one's beliefs to increased levels of serotonin. Usually, assumptions and biases regulate how one would perceive their reality. This phenomenon of relaxed beliefs under the influence of psilocybin provides the individual with a "flattened energy landscape" for new learning to occur, which demonstrates growth through a state of altered consciousness (Carhart-Harris, R. L., & Friston, K. J., 2019a). What this essentially means is the ingrained beliefs at the top of the hierarchical processing possessed by an individual are more disordered (as mentioned in the entropic brain hypothesis) or relaxed and provide leeway for new cognitive structures to be formed within the brain.

Personal growth post administration

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Multiple studies conducted by (Griffiths et al., 2006, 2008, 2011, 2017; MacLean et al. 2011) on healthy volunteers have established that persisting positive changes in attitudes, sociability, mood, life satisfaction, and behaviour have occurred up to 14 months after administration of psilocybin. During a study conducted by Griffith et. al in 2017, 75 participants were divided into three experimental groups based on levels of psilocybin dosage and spiritual practice support. Each participant underwent a 7 hour long session, during which the same music program was played and the session guides were silent, only encouraging participants to focus on their inner experiences. Throughout the session, cardiovascular activity and moods were measured. Questionnaires such as the Hallucinogenic rating scale, 5-Dimension Altered States of Consciousness, Mysticism Scale, and the States of Consciousness Questionnaire were completed by participants 7 hours after drug administration. At the 6-month follow up, the persisting effects questionnaire measured changes in attitudes, mood, altruism, and behaviour.

The main results included the high dosage group scoring higher on altruistic/positive social effects, positive behaviour changes, and increased spirituality, with a large effect size for comparisons between the three groups (Cohen's d = 1.65). Another study conducted by Maclean et. al on participants above the age of 30 confirmed that the personality trait of openness to experience significantly increased after a high-dosage psilocybin session. Participants who had a mystical experience reported enduring effects of openness. A mystical experience is characterised by "feelings of unity and interconnectedness with all people and things, a sense of transcending normal time and space, feelings of peace and joy..."(Hood, 2003; Stace, 1960).

Ayahuasca and DMT

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Fig 4. DMT induced visuals

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N,N- Dimethyltryptamine

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N,N-Dimethyltryptamine or DMT is an endogenous (synthesized by the body) hallucinogenic. DMT crystals are commonly inhaled through a pipe and nearly instantaneously produce the shortest but most profound and powerful psychedelic experience known to mankind. The hallucinogenic trip is usually initiated with a 'whirring' sound and followed by very vivid, geometric visuals and on some occasions, the sensation of leaving one's body and transcending into another realm. A study conducted by Timmermann et. al (2018) concluded that characteristics of a DMT trip are similar to those of a near-death experience (NDE); although it must be noted that both of these states are subjective and a direct, objective causality between the two cannot be determined.

During this experiment, 14 participants (mean age: 34.4 years) were intravenously administered one dose of DMT each, ranging from 7-20mg, followed by a placebo one week afterwards. Participants were asked to fill in the NDE scale that consisted of 16 items and four subscales: (1) Cognitive, (2) Affective, (3) Transcendental, and (4) Paranormal. This was formulated after a study conducted on 67 participants who had undergone real NDE's[grammar?] (Greyson, 1983). The threshold for a NDE is a score of 7 or above on the NDE scale and all the participants met or exceeded this threshold, which implies an overlap of phenomenology between DMT-induced NDE experiences and real NDE experiences (Britton, W. B., & Bootzin, R. R., 2004).

The other questionnaires administered were the Ego Dissolution Inventory (EDI) and the Mystical Experience Questionnaire (MEQ). There was a strong correlation between the factor of "Mystic" on the MEQ, which pertains to the feeling of connectedness and loss of sense of self, and the total NDE score. This is connected to the sense of criticality, or state of primary consciousness, as mentioned earlier in the Entropic brain hypothesis. It has been proposed that this sense of unity with the world is linked to the improvement in one's psychological wellbeing (Groth-Marnat, G., & Summers, R., 1998).

Ayahuasca in indigenous ceremonies

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Fig 5. Brewing of ayahuasca

Ayahuasca is a vital part of many Shamanic ceremonies. This brew of Amazonian origin is concocted from Banisteriopsis caapi and Psychotria viridis; which contain harmala alkaloids and N,N-dimethyltryptamine (DMT), respectively. Harmala alkaloids are substances that facilitate the activity of DMT through the inhibition of monoamine oxidase (MAO) in the liver.

Ayahuasca, which translates to "Vine of the soul" in Quechuan, has been used in traditional Amazonian rituals since 900-1170 AD. Two weeks prior to the ceremony, participants are strongly encouraged to set intentions towards what they want to achieve from the psychedelic experience, as one is confronted by their deepest fears during the trip (Kjellgren, A. et al., 2009).

Motives to attend ayahuasca ceremonies or 14 day camps usually include furthering their self knowledge, personal growth, spiritual growth, or overcoming substance dependence (Loizaga-Velder, A., & Verres, R., 2014). According to literature, these intentions translate into positive effects when it comes to emotional regulation or intelligence. Non-judging, acting with awareness, and observation of surroundings increased one day after the Ayahuasca experience, which are all aspects of mindfulness (Uthaug et. al, 2018). Additionally, a two month follow up demonstrated increased cognitive flexiblility[spelling?], which involves the ability to change fixed patterns of thinking. This relates back to open mindedness and increases the individual's potential to grow mentally.

Lysergic Acid Diethylamide (LSD)

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Discovery and mechanism

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Lysergic Acid Diethylamide (LSD), colloquially known as 'acid', is associated with raves and seeing colours 'melt'. Its accidental discovery by a Swedish chemist, Alfred Hoffman, in 1943 led to him having dizzying hallucinations during a bike ride (which is also why the 19th of April is known as Bicycle day). Eventually, the novel and inexplicably profound experiences led to pro-psychedelic movements in the 1970s.

Fig 7. LSD induced imagery (Artistic depiction)

Effects on wellbeing and altruism

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Multiple studies display that mystical out of body experiences and LSD-induced altered states consciousness are linked to long lasting, positive changes (Liechti & Schmid, 2018; Liechti et al., 2017a; Dolder et al., 2016; Schmid, 2015.)

Liechti and Schmid conducted a study (2018) on the long lasting subjective effects of LSD on 16 healthy subjects that were dosed with 200μg of LSD. The major findings were that the total MEQ scores correlated with Persisting Effects Questionnaire (PEQ) wellbeing/ life satisfaction scores at 12 months (Rs = 0.60, P < 0.05). This is further supported by evidence of participants reporting higher levels of bliss and insightfulness after receiving the same dosage (Liechti et. al., 2017b), which also led to an increased sense of empathy.

Another study by Dolder et al. (2016) confirmed that LSD enhanced emotional empathy for positive emotional situations along with producing acute prosocial effects. Contrastingly, the drug decreased cognitive empathy for negative emotions, which refers to the recognition of emotions; while emotional empathy refers to the ability to share the emotions of another person. It can be inferred that the acute and long term affects of LSD is rooted in its empathogenic effects, although the reason remains unclear (Holze, F. et al., 2021).

It is important to note that adverse effects of LSD are sustained up to 24 hours post administration upon receiving a high dosage and can include dizziness, headaches, fatigue, and exhaustion. The more severe and psychologically damaging effects of a bad LSD trip are the aggravation of symptoms for mood disorders such as schizophrenia, bipolar disorder, psychosis, and anxiety-inducing flashbacks; as per an archival review conducted by Larsen (2016). This review focused on patients who were compensated for psychological injury caused by LSD therapy in the Danish public health care system from Jan 1st, 1960 and enumerates that LSD's potentially neurotoxic qualities can be better tolerated by individuals with milder psychopathological issues.

It can be inferred from the aforementioned studies that the set and setting, i.e the participant's mental state and environment, can influence the likelihood of mystical experiences and overall therapeutic effects.

Quiz time!

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1 Ayahuasca trips are short and mild:

True
False

2 Psilocybin affects the levels of serotonin:

True
False

3 LSD reduces empathy by overloading our senses:

True
False


Psychedelic-assisted therapy and microdosing

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Increasing prominence of 3,4-Methylenedioxymethamphetamine (MDMA)

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MDMA or ecstasy is strongly associated with raves and music festivals due to its extreme mood elevating effects. A lesser known fact is the usage of the drug in the treatment of depression or Post-traumatic stress disorder (PTSD), although it is not as widely used as psilocybin due to its numerous and harsh side effects such as nausea, dry mouth, fatigue, lack of appetite, insomnia, high blood pressure, depressive symptoms, palpitations, and sweating (Liechti, M. E., & Vollenweider, F. X., 2000).

PTSD is characterised by intense reliving of the traumatic event through disruptive memories/nightmares, avoidance of reminders of the event, negative cognitions and mood, and hyperarousal; according to the DSM-5. The Clinician-Administered PTSD Scale (CAPS-5) measured the symptoms of 90 participants before and after a clinically controlled dosage of MDMA (Yazar-Klosinski B., 2021). The CAPS-5 scores of participants in the intervention group decreased 2 months after the trial. The reason for its therapeutic effects is suggested to be the regulation of fear-based behaviours through higher levels of serotonergic function in the amygdala, which is the subcortical brain structure that processes and stores memories associated with fear.

Psilocybin

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Multiple studies have shown the effectiveness of psilocybin in the reduction of treatment-resistant depressive symptoms (Carhart-Harris et al., 2018; Carhart-Harris et al., 2017; Watts. R. et al., 2018). Treatment-resistant depression refers to depressive symptoms that chronically persist irrespective of numerous interventions or treatment. A study comparing psilocybin with conventional antidepressants such as escitalopram suggested that psilocybin allowed patients to fully engage with their emotions through increased amygdala responsiveness; as opposed to escitalopram, which muted emotions and down-regulated responsiveness (Mertens, L. J. et al., 2020). Instead of numbing emotions, they are dealt with in a constructive manner and positive emotions are experienced to the fullest due to heightened levels of serotonin.

Fig 8. Psychedelic-assisted therapy

Microdosing

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Taking small doses of psychedelic substances once every 2-3 days such as LSD and psilocybin to improve mental health and wellbeing or cognitive performance is known as microdosing (Lea, T. et al., 2020a). The online Psychedelic Experience survey (see here) recruited 1533 participants and focused on 525 of them (mean age = 34.5 years, the majority of which were men) that were reportedly microdosing at the time of the survey. Enhanced connectedness, improved mood, and reduced anxiety were the most commonly reported effects, which has implications for further research on the therapeutic effects. Interestingly, increased focus and overall enhanced cognitive abilities were reported by those who microdosed on LSD, reinforcing the psychopharmacological differences between the two hallucinogens (Lea, T. et al., 2020b).

Theories underlying psychedelic-assisted behavioural change

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Increased levels of open mindedness and interconnectedness are the most commonly reported acute and long term effects of psychedelic experiences and they have a significant impact on personal growth.

Health behaviour change

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The relaxed beliefs under psilocybin (REBUS model) points towards a respite from internalized or rigid beliefs such as cravings in addictions, negative cognitive biases in depression, or bodily beliefs in body dysmorphia. This opens up a window of change when combined with therapy and exploratory behaviour consistent with the new beliefs or open mindedness gained during the psychedelic experiences (Teixeira, P. J. et al., 2021). A flattened energy landscapes[spelling?] enables new schemas or patterns of thinking to be created as well as exploratory behaviour consistent with the newly acquired beliefs post psychedelic experiences, such as spending more time outdoors and being more environmentally conscious due to an enhanced sense of relatedness with nature (Forstmann, M., & Sagioglou, C., 2017a)

Self determination theory

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The three psychological needs underlying the self determination theory are autonomy, competence, and relatedness. It is common for an individuals's sense of autonomy to be enhanced after a positive psychedelic experience through gaining a deeper insight into their identity and being more in tune with their inherent needs. Feeling a sense of purpose or meaningfulness provides more direction to one's life and enhances a sense of competence in day to day functioning (Forstmann, M., & Sagioglou, C., 2017b)

Build-and-broaden theory

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A plausible explanation is within the build-and-broaden theory (Fredrickson, B. L., 2001), one of the major frameworks of modern positive psychology. This theory states that thought-action repertoires (specific thoughts linked to an emotion) are widened with positive, or in this case, mystical experiences. For example, if one has a narrow thought-action repertoire, feeling jealous about their coworker getting a promotion instead of them can lead to thoughts such as "I am going to be stuck in this position for a really long time because of my incompetency" or "The boss does not recognise my efforts and is biased". Alternatively, a broader thought-action repertoire leads them to think "If X can get the promotion, so can I, I'm just as qualified and experienced", "Maybe my efforts are not prominent enough, I will simply have to work smarter", or "X deserved the promotion for all the hard work they put in over the last quarter and I am happy for them".

Possessing greater cognitive flexibility with thoughts associated with an emotion relates to open mindedness towards a variety of experiences. The psilocybin-induced "flattened energy landscape" enables novel cognitive processes and connections to be formed (Carhart-Harris, R. L., & Friston, K. J., 2019b). This increase in open mindedness leads to behaviours that develop or grow personal strengths such as resilience, optimism, curiosity, wisdom, compassion, gratitude, meaning, and spirituality; all of which are conducive to personal growth (Walsh R., 1983).

Conclusion

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Psychedelics are unique drugs that have multiple means of connections towards our subconscious. It can be inferred from research that they open up a window for growth through processes such as relaxing of one's beliefs, hyperassociative states that increase one's sense of relatedness, cognitive flexibility, and broadened thought-action repertoires.

The "mind-revealing" properties of these substances make the relationship that one has with themselves prominent and has positive implications for therapy as well as getting in touch with one's "true" self. Psychedelics are not for everybody and one must have a relatively stable mindset and a certain level of control over their emotions and cognition, as a major part of the experience involves letting go of your sense of self, especially with intense mild-altering substances such as Ayahuasca and DMT.

As the research is mostly based on self-reporting, it may not provide the researchers with concrete causal inferences as the experiences an individual has under the influence of psilocybin are subjective. Further neuroimaging studies or informant-reported follow-up tests would provide more empirical evidence on psilocybin's effect on an individual's growth. Sequential studies on diverse cohorts over the period of 3 years would provide a deeper insight into the long-term effects of psychedelics on individuals from multiple backgrounds with different beliefs or mindsets.

See also

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References

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Bicycle day: The accidental discovery of LSD. (2017). Laboratory Equipment

Britton, W. B., & Bootzin, R. R. (2004). Near-Death Experiences and the Temporal Lobe. Psychological Science, 15(4), 254–258. https://doi.org/10.1111/j.0956-7976.2004.00661.x

Carhart-Harris, R. L., Bolstridge, M., Day, C. M. J., Rucker, J., Watts, R., Erritzoe, D. E., ... & Nutt, D. J. (2018). Psilocybin with psychological support for treatment-resistant depression: six-month

follow-up. Psychopharmacology, 235(2), 399-408. https://doi.org/10.1007/s00213-017-4771-x

Carhart-Harris, R. L., & Friston, K. J. (2019). REBUS and the Anarchic Brain: Toward a Unified Model of the Brain Action of Psychedelics. Pharmacological Reviews, 71(3), 316–344. https://doi.org/10.1124/pr.118.017160

Carhart-Harris, R. L., Leech, R., Hellyer, P. J., Shanahan, M., Feilding, A., Tagliazucchi, E., Chialvo, D. R., & Nutt, D. (2014). The entropic brain: a theory of conscious states informed by neuroimaging research with psychedelic drugs. Frontiers in Human Neuroscience, 8, 20–20. https://doi.org/10.3389/fnhum.2014.00020

Carhart-Harris, R. L., Roseman, L., Bolstridge, M., Demetriou, L., Pannekoek, J. N., Wall, M. B., ... & Nutt, D. J. (2017). Psilocybin for treatment-resistant depression: fMRI-measured brain mechanisms. Scientific reports, 7(1), 1-11. https://doi.org/10.1038/s41598-017-13282-7

Forstmann, M., & Sagioglou, C. (2017). Lifetime experience with (classic) psychedelics predicts pro-environmental behavior through an increase in nature relatedness. Journal of Psychopharmacology, 31(8), 975–988. https://doi.org/10.1177/0269881117714049

Fredrickson, B. L. (2001). The Role of Positive Emotions in Positive Psychology: The Broaden-and-Build Theory of Positive Emotions. The American Psychologist, 56(3), 218–226. https://doi.org/10.1037/0003-066X.56.3.218

Groth-Marnat, G., & Summers, R. (1998). Altered Beliefs, Attitudes, and Behaviors Following Near-Death Experiences. The Journal of Humanistic Psychology, 38(3), 110–125. https://doi.org/10.1177/00221678980383005

Holze, F., Avedisian, I., Varghese, N., Eckert, A., & Liechti, M. E. (2021). Role of the 5-HT2A Receptor in Acute Effects of LSD on Empathy and Circulating Oxytocin. Frontiers in Pharmacology, 12, 711255–711255. https://doi.org/10.3389/fphar.2021.711255

Huxtable, R. J. (1992). The Mushrooming Brain -- Food of the Gods: The Search for the Original Tree of Knowledge by Terence McKenna. Nature, 356(6370), 635–. https://doi.org/10.1038/356635a0

Kettner, Hannes, et al. "Psychedelic communitas: intersubjective experience during psychedelic group sessions predicts enduring changes in psychological wellbeing and social connectedness." Frontiers in Pharmacology 12 (2021): 623985

Larsen, J. K. (2016). Neurotoxicity and LSD treatment: a follow-up study of 151 patients in Denmark. History of Psychiatry, 27(2), 172–189. https://doi.org/10.1177/0957154X16629902

Lea, T., Amada, N., Jungaberle, H., Schecke, H., & Klein, M. (2020). Microdosing psychedelics: Motivations, subjective effects and harm reduction. The International Journal of Drug Policy, 75, 102600–102600. https://doi.org/10.1016/j.drugpo.2019.11.008

Liechti, M. E., Dolder, P. C., & Schmid, Y. (2017). Alterations of consciousness and mystical-type experiences after acute LSD in humans. Psychopharmacology (Berlin, Germany), 234(9-10), 1499–1510. https://doi.org/10.1007/s00213-016-4453-0

Liechti, M. E., & Vollenweider, F. X. (2000). Acute psychological and physiological effects of MDMA (“Ecstasy”) after haloperidol pretreatment in healthy humans. European Neuropsychopharmacology, 10(4), 289–295. https://doi.org/10.1016/S0924-977X(00)00086-9

Loizaga-Velder, A., & Verres, R. (2014). Therapeutic Effects of Ritual Ayahuasca Use in the Treatment of Substance Dependence—Qualitative Results. Journal of Psychoactive Drugs, 46(1), 63–72. https://doi-org.ezproxy.canberra.edu.au/10.1080/02791072.2013.873157

Lopez, Nicole (2020) "An Exploration of Linguistic Relativity Theory for Considertion of Terence McKenna’s “Stoned Ape Theory” on the Origins of Consciousness and Language: Implications for

Language Pedagogy," Journal of Conscious Evolution,1(6), https://digitalcommons.ciis.edu/cejournal/vol16/iss1/6

MacLean, K. A., Johnson, M. W., & Griffiths, R. R. (2011). Mystical experiences occasioned by the hallucinogen psilocybin lead to increases in the personality domain of openness. Journal of Psychopharmacology (Oxford), 25(11), 1453–1461. https://doi.org/10.1177/0269881111420188

Mertens, L. J., Wall, M. B., Roseman, L., Demetriou, L., Nutt, D. J., & Carhart-Harris, R. L. (2020). Therapeutic mechanisms of psilocybin: Changes in amygdala and prefrontal functional connectivity during emotional processing after psilocybin for treatment-resistant depression. Journal of Psychopharmacology (Oxford), 34(2), 167–180. https://doi.org/10.1177/0269881119895520

Rätsch, C. (2005). The encyclopedia of psychoactive plants: ethnopharmacology and its applications. Simon and Schuster.

Ruffell, S. G. D., Netzband, N., Tsang, W., Daies, M., Butler, M., Rucker, J. J. H., Tófoli, L. F., Dempster, E. L., Young, A. H., & Morgan, C. J. A. (2021). Ceremonial Ayahuasca in Amazonian

Retreats—Mental Health and Epigenetic Outcomes From a Six-Month Naturalistic Study. Frontiers in Psychiatry, 12, 687615–687615. https://doi.org/10.3389/fpsyt.2021.687615

Teixeira, P. J., Johnson, M. W., Timmermann, C., Watts, R., Erritzoe, D., Douglass, H., Kettner, H., & Carhart-Harris, R. L. (2021). Psychedelics and health behaviour change. Journal of Psychopharmacology, 13(1). https://doi.org/10.1177/02698811211008554

Timmermann, C., Roseman, L., Williams, L., Erritzoe, D., Martial, C., Cassol, H., Laureys, S., Nutt, D., & Carhart-Harris, R. (2018). DMT Models the Near-Death Experience. Frontiers in Psychology, 9, 1424–1424. https://doi.org/10.3389/fpsyg.2018.01424

Uthaug, M. V. (2018) et al. Sub-acute and long-term effects of ayahuasca on affect and cognitive thinking style and their association with ego dissolution. Psychopharmacology (Berl.). 235, 2979–2989 https://doi.org/10.1007/s00213-018-4988-3

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 (Orlando, Fla.), 220, 117049–117049. https://doi.org/10.1016/j.neuroimage.2020.117049

Walsh, R. (1983). Psychedelics and self-actualization. Psychedelic reflections, 116-121.

Watts, R., Day, C., Krzanowski, J., Nutt, D., & Carhart-Harris, R. (2017). Patients’ accounts of increased “connectedness” and “acceptance” after psilocybin for treatment-resistant depression. Journal of humanistic psychology, 57(5), 520-564. https://doi.org/10.1177/0022167817709585

Weigold, I. K., Porfeli, E. J., & Weigold, A. (2013). Examining Tenets of Personal Growth Iniiative[spelling?] Using the Personal Growth Initiative Scale-II. Psychological Assessment, 25(4), 1396–1403. https://doi.org/10.1037/a0034104

Yazar-Klosinski, B., & Mitchell, J. (2021). A Randomized, Double-Blind, Placebo Controlled Phase 3 Study Assessing Efficacy and Safety of MDMA-Assisted Therapy for the Treatment of Severe PTSD. Biological Psychiatry (1969), 89(9), 105–105. https://doi.org/10.1016/j.biopsych.2021.02.270

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