Working with Weirdness: A Response to “Moving Past Mysticism in Psychedelic Science”

Breeksema and colleagues respond to a recent Viewpoint proposing that psychedelic science should abandon the concept of mystical experience (ME). They argue that the Viewpoint rests on a misunderstanding of MEs as an esoteric or supernatural category rather than a well-described, empirically investigable class of subjective experiences. The authors contend that dismissing MEs risks ignoring a set of phenomena that are frequently reported after psychedelic use and that appear to have personal and clinical significance. The paper sets out to rebut the claim that MEs are inherently unscientific by emphasising four main points: that the concept of ME has been subject to sustained empirical study; that MEs have clinical and explanatory relevance for therapeutic outcomes; that validated methodological tools exist to study them; and that psychedelic research should embrace, rather than discard, the variety and "weirdness" of psychedelic experiences. The piece is a conceptual and evidentiary response rather than a report of new empirical data, aimed at defending the scientific study of mystical-type and other extraordinary experiences in psychedelic research.

This paper is a scholarly response and conceptual review rather than a primary empirical study. The authors marshal historical and contemporary literature, classical experiments, psychometric instruments, and qualitative methodologies to support their argument. They contrast the Viewpoint's critique with examples from the history of psychology and recent clinical research to show that MEs have been systematically studied. The authors discuss established measurement instruments (for example, scale-based assessments and inventories) and qualitative approaches (in-depth interviews, participant observation, microphenomenology) as part of the methodological toolkit available to researchers studying nonordinary experiences. There is no original data collection, randomisation, or statistical analysis reported; instead, the approach is argumentative and synthesises prior findings and methodological developments to make the case for continued and broadened study of MEs.

The paper presents several lines of evidence and argumentation. First, the authors distinguish between popular or colloquial notions of mysticism (as supernatural or arcane) and the operationalised, agnostic construct of mystical-type experiences used in scientific research. They argue that scientific study does not presuppose metaphysical truth-claims about the experiences. Second, they summarise historical and clinical findings showing that psychedelics can occasion experiences matching classical descriptions of MEs. The authors cite William James's core features (noetic quality, transience, ineffability) and note additional commonly identified elements such as transcendence of space and time, unity, awe, and positive emotions. They reference early controlled work showing that psilocybin can reliably occasion MEs and report long-term positive life impacts from such experiences. More recent clinical research is summarised as showing correlations between occurrence of MEs during psychedelic sessions and enduring therapeutic benefits in conditions including end-of-life anxiety, depression, and substance use disorders; the authors note that evidence is strongest for classical psychedelics but that MDMA and ketamine may also occasion ME-like phenomena that relate to outcomes. Third, the authors document the availability and validation of psychometric tools and qualitative methods for studying MEs. They list well-known instruments (for example, the Hood Mysticism Scale, the Mystical Experience Questionnaire, the Ego Dissolution Inventory, and the 5-Dimensions of Altered States of Consciousness scale) and highlight the Inventory of Non-Ordinary Experiences, which helps separate reported phenomena from participants' interpretations. They also advocate for qualitative and microphenomenological techniques to capture subjective detail. Finally, the authors report concerns about contemporary research trends that downplay subjective experiences—examples include a focus on microdosing, efforts to develop non-hallucinogenic analogues, labelling subjective effects as unwanted side effects, and the potential for commercial and medical access to be concentrated among WEIRD (Western, Educated, Industrialised, Rich, Democratic) populations. They argue these trends underline the need to study a broad range of experiences across diverse cultural settings rather than discard ME as a category.

The authors interpret their synthesis as a rebuttal to the proposal that mystical concepts should be purged from psychedelic science. They argue that MEs constitute a legitimate, empirically accessible domain that is both clinically relevant and explanatorily informative. Rather than importing supernatural assumptions, scientific work on MEs remains agnostic about metaphysical claims and focuses on phenomenology, mechanisms, and outcomes. They position their view relative to earlier research by tracing a continuous line from William James and mid-20th-century controlled studies to contemporary clinical trials showing mediation of therapeutic effects by ME-like experiences. The authors emphasise that multiple explanatory domains (neurobiological, psychological, autobiographical, cognitive, mystical) coexist and can offer partial, overlapping accounts; given the idiosyncratic, context-dependent nature of psychedelic effects, no single framework is likely to suffice. Key limitations and uncertainties are acknowledged: science may not yet have all tools to fully explain these "weird" experiences, the emphasis on MEs could be excessive, and existing samples are disproportionately WEIRD, which limits generalisability. The authors recommend broader methodological pluralism (including psychometrics and qualitative methods), cross-cultural research, attention to setting and expectations, and a therapeutic ethic that helps patients integrate revelatory experiences without asserting ontological truths. They warn against two undesirable responses: replacing MEs with a new form of "neuro-enchantment" that reduces experiences solely to brain mechanisms, or discarding MEs because they are challenging to study or carry problematic colloquial associations. Instead, they call for embracing the variety and weirdness of psychedelic experiences and using the full scientific toolkit to investigate them.