Psychedelics alter metaphysical beliefs

Psychedelics alter metaphysical beliefs Can the use of psychedelic drugs induce lasting changes in metaphysical beliefs? While it is popularly believed that they can, this question has never been formally tested. Here we exploited a large sample derived from prospective online surveying to determine whether and how beliefs concerning the nature of reality, consciousness, and free-will, change after psychedelic use. Results revealed significant shifts away from ‘physicalist’ or ‘materialist’ views, and towards panpsychism and fatalism, post use. With the exception of fatalism, these changes endured for at least 6 months, and were positively correlated with the extent of past psychedelic-use and improved mental-health outcomes. Path modelling suggested that the belief-shifts were moderated by impressionability at baseline and mediated by perceived emotional synchrony with others during the psychedelic experience. The observed belief-shifts post-psychedelic-use were consolidated by data from an independent controlled clinical trial. Together, these findings imply that psychedelic-use may causally influence metaphysical beliefs—shifting them away from ‘hard materialism’. We discuss whether these apparent effects are contextually independent. Metaphysics is a branch of philosophy that studies themes such as the fundamental nature of reality, consciousness, and free will1. Research has shown that most people hold distinct metaphysical positions—even if we are not fully aware of it2,3,4,5,6,7. Metaphysical beliefs interface with such basic domains as health, religion, law, politics and education8,9,10,11,12, and are entwined with a society’s culture and its stability13.Paradigmatic metaphysical positions can be found in physicalism (or materialism), idealism and dualism. Proponents of physicalism maintain that the nature of reality is fundamentally physical and all mental properties derive from this basic property, the position of idealism states that all physical properties derive from a fundamental reality which is mental (e.g., an irreducible, fundamental and pervasive consciousness) and dualism states that the nature of reality consists of two separate properties (i.e., the physical and mental)1.Although often held implicitly, metaphysical beliefs can become explicit during or after particularly intense life experiences or transient altered states14,15, such as near-death experiences16, meditation17, hypnosis18, experiences of ‘awe’19, traumatic events15,20, and psychedelic drug-induced experiences21,22,23,24,25,26.Focusing specifically on psychedelics, recent evidence has demonstrated that psychedelics can reliably and robustly induce intense, profound, and personally meaningful experiences that have been referred to as ‘mystical-type’27, ‘spiritual’28, ‘religious’29, ‘existential’30, ‘transformative31, ‘pivotal’15 or ‘peak’32. Some specific facets of these potentially transformative psychedelic experiences include: a perceived transcendence of the physical bounds and laws of this ‘consensus reality’23,24,25,26, encounters with ‘supernatural’ beings26,29 and an ‘ultimate reality’29, and the witnessing or comprehending of spatial and temporal vastness, a sense that the ‘cosmos is fundamentally conscious’25 and/or that all things are essentially inter-related or connected, i.e. the so-called ‘unitive experience’33.From a mechanistic perspective, the unitive experience is arguably the most tangible feature of these experiences33,34. It is closely related to the so-called ‘overview effect’35, ‘universal insight’35, experience of ‘awe’19,35,36 and ‘non-dual’ states37. Such experiences (often reported as inducing an ‘ontological shock’38) appear to have a powerful capacity for mediating major shifts in perspective19,31,39, including shifts in metaphysical beliefs.Psychedelics have been found to acutely increase psychological suggestibility, likely by relaxing the confidence of held beliefs40,41 thereby allowing for an easier transmission of others’ implicitly and explicitly held beliefs into one’s own42. This phenomenon may be particularly pertinent in the context of collective psychedelic experiences43.Anecdotal, qualitative and retrospective reports hint that psychedelics can change metaphysical beliefs25,26,44, and these shifts are often explained post-hoc as having been triggered by revelations or insights45. However, there have been no formal, systematic, controlled and quantitative investigations of this phenomenon46. It has been proposed that such investigations might advance both the scientific and philosophical understanding of the psychedelic experience and its transformative effects47.To address this important knowledge gap, the present study sought to examine three key questions. 1. Can psychedelics causally affect core beliefs concerning the nature of reality, consciousness and free will? 2. What is the relationship between any such belief-changes and mental health? 3. What psychological mechanisms may be involved in the putative belief-shifts? For this purpose, we developed a prospective survey requiring respondents to answer questions pertaining to a range of metaphysical beliefs before and after attending a ceremony in which a psychedelic compound was taken. The external validity of these findings was subsequently examined via comparison with data derived from a randomized, controlled clinical trial in major depressive disorder, in which changes in beliefs were measured following psilocybin-therapy vs. a 6-week course of the selective-serotonin-reuptake-inhibitor, escitalopram.866 respondents completed the survey enquiring about their metaphysical beliefs at different timepoints (see ‘Methods’, ‘Supplementary Results’, and Supplementary Table 1 for sample characteristics). Thirteen items comprise the newly developed Metaphysical Beliefs Questionnaire and were chosen or formulated in a way to approximate classic metaphysical positions in jargon-free, non-specialist terms. The precise relationship between these items and specific philosophical positions could be contested, and so are arguably best treated at face-value. For purposes of concision and context, we did choose to ascribe some philosophical terms to the individual items and a factor dimension (Table 1) but also encourage that they be viewed as open to interpretation.Table 1 Exploratory factor analysis of the Metaphysical Beliefs Questionnaire.A factor analysis on the ten self-constructed belief items developed specifically for the survey, together with three items derived from previous research6, revealed a single belief factor comprised of nine items, which we labelled Non-physicalist Beliefs (NPB; see ‘Methods’ for factor analysis results). This single factor showed good internal consistency (Cronbach’s alpha = 0.86) and included positive loadings (> 0.4) for items related to beliefs in separate and supernatural realms of existence, a non-natural unifying principle in reality, panpsychism, dualism, and solipsism/idealism. Items that loaded negatively (< − 0.4) referred to ‘hard' monistic materialist or physicalist positions, or a belief in natural (as opposed to super-natural) explanations for phenomena in the universe (naturalism). These items and their loadings are shown in Table 1.We compared NPB scores before attending a ceremony involving psychedelic use (baseline) with NPB scores 4 weeks and 6 months after the ceremony. Pooling scores for the NPB factor, analyses revealed a significant shift away from physicalism at 4 weeks compared with baseline (t(121) = 3.66, p = 0.001, d = 0.33, confidence interval, 95% CI [0.12, 0.39]). These changes were sustained 6 months after the ceremony (t(121) = 5.07, p < 0.0001, d = 0.46, 95% CI [0.22, 0.50]) (Fig. 1a). Larger effect sizes were found for respondents who were embarking on their first psychedelic experience (the so-called ‘psychedelic naïve'), with significant changes found at 4 weeks (t(52) = 3.85, p = 0.001, d = 0.53, 95% CI [0.21, 0.66]) and 6 months (t(52) = 5.32, p < 0.0001, d = 0.73, 95% CI [0.36, 0.80]) (Supplementary Fig. 1a). Analyses of each individual item for the NPB factor revealed increases in notions of transcendentalism, mind–body dualism, and panpsychism—among others, with some changes remaining significant for 6 months (see Fig. 1b-left and Supplementary Fig. 1b for findings for ‘naïve' respondents). Additionally, a significant positive correlation was found between previous psychedelic use and shifts away from the hard-materialism pole of the hard-materialism vs. hard-dualism spectrum (Fig. 1b-right) at baseline (r = 0.223, p < 0.0001).Figure 1Psychedelic use is associated with shifts in metaphysical beliefs away from hard physicalism or materialism. Attending a psychedelic ceremony was associated with shifts away from hard-materialistic views (a-left), and items associated with transcendentalism, non-naturalism, panpsychism, primacy of other realms, dualism and solipsism/idealism (b-left), with some changes enduring up to 6 months (Bonferroni-corrected). Additionally, significant positive relationships were observed between lifetime psychedelic use and baseline scores on metaphysical beliefs (a-right), and items referring to transcendentalism, non-naturalism, and panpsychism, while a negative relationship was found with materialism (b-right). (b-left: mean values and standard errors displayed. *Significant change at 4 weeks; **significant change at 6 months, Bonferroni-corrected; b-right: * p < 0.0001, Bonferroni-corrected).FatalismAnalysis of the prospective data (i.e., pre versus post ceremony) revealed that the psychedelic ceremony was associated with increases in scores of Fatalistic determinism4 (see 'Supplementary Methods' for the items used) at 4 weeks versus baseline (t(121) = 2.81, p = 0.012, d = 0.25, 95% CI [0.06, 0.37]); however, this effect did not persist at 6 months. For psychedelic-naïve participants, larger effect sizes were detected at 4 weeks compared with baseline (t(52) = 3.38, p = 0.003, d = 0.46, 95% CI [0.16, 0.63]), and the changes persisted for at least 6 months (t(52) = 2.86, p = 0.012, d = 0.39, 95% CI [0.11, 0.64]) (Supplementary Fig. 2a). Consistent with the results described above, correlational analysis revealed a mild (r = 0.186) but significant positive correlation (p < 0.0001) between baseline beliefs in Fatalistic Determinism and lifetime psychedelic-use (see Supplementary Figs. 2b and 3 for correlations between scales at different timepoints).Conversion of preferred metaphysical beliefsTo further explore the relationship between psychedelic use and shifts in participant's metaphysical positions, we separated the sample into four groups corresponding to which metaphysical position participants mostly strongly endorsed at baseline. Respondents with either no positive endorsement or scoring equally high on more than one item were grouped under the label ‘none/mixed', otherwise they were categorised as either: dualists, idealists or materialists. Results showed that baseline ‘hard-materialists' tended to shift away from this position after psychedelic use. In fact, such shifts were more common than not. We also found that among those who did shift, the nature of the shift was either towards the ‘none/mixed' position or ‘hard-dualism'. Intriguingly, shifts away from polar metaphysical views to more moderate, ‘softer' positions, was also evident for a large portion (37%) of baseline ‘hard-dualists' who tended to reject any preference or endorse an equanimous (i.e. mixed) position post-psychedelic-use (Fig. 2a,b). Separately, however, we observed that those who held more moderate views on panpsychism became more convinced of this position post-psychedelics (labelled ‘believers') (Fig. 2c,d). These prospective findings were matched by correlations between lifetime psychedelic-use and stronger panpsychist and weaker materialist views, at baseline (Fig. 2e).Figure 2The nature of belief-shifts post-psychedelic-use. Matrices displaying the rate of belief-shift from and towards different ‘hard' metaphysical positions are displayed at 4 weeks (a-above) and 6 months (b-above) following the ceremony. Significant rates of change were found only for respondents' endorsing materialism at 4 weeks (a-below) and 6 months (b-below), with most of these ‘hard materialists' leaning towards dualism or equanimity (or reduced hard materialism) post-ceremony. Significant rates of belief-shift were also found for respondents with non-committal views on panpsychism at baseline, who then shifted towards a panpsychist ‘believer' stance at 4 weeks (c) and 6 months (d) post-ceremony. (e) Lifetime psychedelic use was positively correlated with panpsychist views and negatively correlated with hard materialistic views measured at baseline. (*p < 0.05, **p < 0.01, ***p < 0.001).Non-physicalist beliefs and well-beingA significant positive correlation was found between shifts away from hard-materialism (the NPB factor) and changes in well-being. The correlation was significant at 4 weeks and at 6 months post-ceremony (Fig. 3).Figure 3Shifts away from hard material
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