Ethics of Psychedelic-Assisted Therapy

Michelle Matvey and Parker Kelley, PhD
November 2, 2022
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Photo by Raimond Klavins on Unsplash

A recent study of two independent cohorts taking psychedelics in two very different settings found consistent results: psychedelics have the potential to alter metaphysical beliefs [1]. Metaphysical beliefs are our ideas about the fundamental nature of reality, consciousness, and free will. They shape our opinions on topics such as health, law, religion, politics, and education [2].

The study examined reported changes to the following metaphysical beliefs post-psychedelic use: materialism, idealism, dualism, panpsychism, and fatalism. Materialism holds that there is only material “stuff” in the universe. Therefore, there can only be a single type of causation, which is physically measurable and explainable through scientific inquiry. Idealism holds that there is only mind “stuff,” and all causation in the universe comes from the mind. These views contrast with forms of dualism, which accept both types of “stuff,” but differ in how they explain the interaction of mind and matter. Panpsychism is a form of idealism that holds that the mind or a mindlike aspect is a fundamental and ubiquitous feature of reality, and fatalism is the idea that all events can be explained by fate or destiny or are predetermined due to the causal closure of the universe. An alternative to the metaphysical beliefs described above is epistemic humility, which emphasizes that all knowledge of the world is filtered, interpreted, and structured by the observer. In other words, we will never have access to the world in itself and cannot ever really be confident in any metaphysical position. We propose that epistemic humility may be a helpful framework for processing psychedelic-mediated belief changes due to its belief-agnosticism.

The study included one group of people (i.e. cohort) who responded to an online survey of psychedelic use, and the second cohort included individuals who participated in a controlled clinical trial. In the survey study, individuals planning to take psychedelics in either a guided or ceremonial context, such as an Ayahuasca retreat or psychedelic assisted psychotherapy (psilocybin/magic mushrooms/truffles, Ayahuasca, N,N-dimethyltryptamine (DMT), San Pedro (mescaline), LSD/1P-LSD), were recruited via online advertisements and invited to sign up [1]. One week prior and four and six weeks after their experience, participants answered questions about their metaphysical beliefs. Before and after their psychedelic experience, participants were asked to indicate their agreement with statements such as: “There exists another separate realm or dimension beyond this physical world that can be experienced or visited,” and “The physical world is an illusion generated by consciousness or the mind.” These statements were designed to assess participants’ agreement with concepts such as dualism, materialism, and idealism [3].

From before to after the psychedelic experience, people generally reported being less confident in materialism and identifying more with dualism, panpsychism, and fatalism. Not only did individuals’ beliefs shift away from materialism, but also, those who experienced such changes reported believing more strongly in dualism or panpsychism. Shifts away from materialism were associated with improvements in well-being. This suggests that: 1) psychedelics cause patients to shift away from belief in materialism, and 2) decreases in belief in materialism after psychedelics predict better mental health outcomes in patients, or in coarse terms, less materialism may be “good” for you.

In the second cohort included in the study, data was collected in a randomized, controlled clinical trial in people with major depressive disorder, in which changes in patients’ beliefs were measured following psilocybin-therapy vs. a six-week course of the antidepressant medication escitalopram [1]. At baseline and six weeks following the start of treatment, patients were presented with the same statements regarding metaphysical beliefs and asked to indicate their level of agreement. Similarly, patients who received psilocybin reported a shift towards non-materialist beliefs, while those in the escitalopram group did not experience a significant change. Furthermore, patients who got better (their symptoms of depression were less severe after treatment compared to baseline), experienced significantly greater shifts away from materialist beliefs. Again, these results suggest that psychedelics can shift beliefs, and that belief-shifts away from materialism may correlate with positive mental health changes (captured as improvements in well-being in observational data and improvements in depression scores in controlled research data), i.e. psychedelic-induced shifts away from materialism may be “good” for the patient population represented in this study.

However, shifts towards the center, which we will call “epistemic humility,” were also observed in 37% of respondents in the survey study who were described as “hard dualists” at baseline. There is at present no analysis of whether these shifts also correlated with improved well-being or depression. Further analysis of existing data sets is needed to determine the extent to which an individual’s beliefs at baseline impact the observed shifts and whether the direction of the shift predicts changes in well-being (i.e. if only shifts away from materialism are associated with increased well-being, or if shifts toward epistemic humility are as well). Therefore, we propose an alternative hypothesis based on the REBUS theory proposed by Robin Carhart-Harris and Karl Friston, which suggests that the primary effect of psychedelics is to relax higher order beliefs [4]. It is possible that the effect of psychedelics is to facilitate a reassessment of beliefs in some individuals, rather than driving a directional shift towards any specific metaphysical view. Factors like shared cultural beliefs, baseline individual beliefs, level and type of education, and other individual and collective factors may play a role in which populations are most likely to experience which shifts in belief, but further prospective experiments in this domain will be required to suss out the validity of this hypothesis and the relevant factors. In this regard, the concept of epistemic humility is emerging as a value in some psychedelic “healing” circles and may act as an inoculation against potential side effects of psychedelic use [5], as it qualifies belief changes with the framework that no one metaphysical position can be definitively correct. Therefore, changes to one’s metaphysical beliefs can be tolerated and taken somewhat lightly by those experiencing such changes.

If psychedelics can cause such profound transformations in beliefs, what does this mean for the informed consent process? How can you truly prepare patients for the possibility that fundamental ideas essential to their ways of understanding the world might change overnight? Anecdotal reports from clinicians suggest that participants who have experienced such shifts like their new belief system, but how might their pretreatment selves have viewed this transformation? It is helpful to note that psychedelic therapy is not the first medical intervention to raise questions of psychological preparedness for dramatic changes to the self. For example, obese patients seeking bariatric surgery must undergo psychiatric evaluation to help assess their readiness for the significant stressors and lifestyle changes associated with a smaller body size [6]. Similarly, it may be difficult for participants in psychedelic clinical trials to anticipate their experience post-treatment. Another parallel is changes to core personality domains that sometimes occur in the course of traditional psychotherapy or during treatment for psychiatric illness more generally [7]. An especially salient circumstance is the treatment of personality disorders in which the intention of therapy is to alter features of personality [8]. We also should avoid “psychedelic exceptionalism” by suggesting that this process is entirely unique to psychedelic-assisted psychotherapy. Experiences ranging from surgery6 to regular psychotherapy [8] to transformative life events [9-11] can result in similar changes.

We suggest that these potential shifts, which map across belief, value, and personality domains [12-14] require extensive discussion during the informed consent process. However, we should avoid infantilizing participants/patients or assuming an inability to process and prepare for the gravity of such changes. Discussions of the possibility and frequency of belief changes after psychedelic therapy and the possibility of engaging with these experiences from a position of epistemic humility should be included in standard treatment protocols, allowing participants the resources and freedom to use their current value systems to decide whether they could tolerate or even welcome such changes prior to participation in psychedelic clinical trials [15].

The relationship between shifts in beliefs and improvements in mental well-being in patients being treated with psychedelics should be explored further, particularly if belief shifts are associated with positive treatment outcomes or alternatively, adverse outcomes. While improvement in well-being is a positive outcome, it is important to note that adoption of non-materialist beliefs can also be associated with maladaptive coping strategies, such as avoidance, escapism, and mistrust of science. For example, skepticism of science, which is associated with non-materialist beliefs, can lead to hesitancy about important public health measures such as vaccines and skepticism of the modern medical system in general. The key seems to lie in balance, as shifts too far towards dualism or panpsychism can lead to paranoia, escapism, and conspiratorial thinking [16,17], while beliefs that are too dependent upon current scientific materialist views of the world may lead to dogmatism, cynicism, loss of meaning, disconnection from the natural world, and a reduced willingness to consider novel or alternative explanations of natural phenomena. Researchers and clinicians in this space must be cognizant of the risk of an “overshoot” of shifted beliefs and how this may cause profound changes to participants’ behaviors.


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2. Peter van Inwagen, M. S. "Metaphysics". The Stanford Encyclopedia of Philosophy (Winter 2021 Edition)

3. Robinson, H. Dualism. Stanford Encyclopedia of Philosophy (2021).

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10. Solnit, R. A paradise built in hell: The extraordinary communities that arise in disaster. (Penguin, 2010).

11. Frankl, V. E. Man's search for meaning. (Simon and Schuster, 1985).

12. Lyons, T. & Carhart-Harris, R. L. Increased nature relatedness and decreased authoritarian political views after psilocybin for treatment-resistant depression. Journal of Psychopharmacology 32, 811-819 (2018).

13. Aixalà, M., Dos Santos, R. G., Hallak, J. E. C. & Bouso, J. C. Psychedelics and Personality. ACS Chem Neurosci 9, 2304-2306 (2018).

14. Bouso, J. C., dos Santos, R. G., Alcázar-Córcoles, M. Á. & Hallak, J. E. C. Serotonergic psychedelics and personality: A systematic review of contemporary research. Neuroscience & Biobehavioral Reviews 87, 118-132 (2018).

15. Jaworska A, Chiong W. Supported Decision-Making for People with Dementia Should Focus on Their Values. Am J Bioeth. 2021 Nov;21(11):19-21. doi: 10.1080/15265161.2021.1980150. PMID: 34710012.

16. Hayes, S. C., Luoma, J. B., Bond, F. W., Masuda, A. & Lillis, J. Acceptance and commitment therapy: model, processes and outcomes. Behav Res Ther 44, 1-25 (2006).

17. Hayes, S. C. A liberated mind: How to pivot toward what matters. (Penguin, 2020).

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