Skip to content

Daniel Villiger

Institute of Philosophy, Zollikerstrasse 117, 8008 Zürich, Switzerland. Electronic address: daniel.villiger@uzh.ch.

12 papers in the library · 146 citations · publishing 2022-2025

Papers

With great power comes great vulnerability: an ethical analysis of psychedelics’ therapeutic mechanisms proposed by the REBUS hypothesis

Journal of Medical Ethics April 12, 2023 Daniel Villiger, Manuel Trachsel 40 citations

Psychedelic-assisted therapy makes patients highly suggestible and sensitive to context by increasing the influence of bottom-up input, which can revise rigid beliefs. This heightened vulnerability, where patients lose control and become dependent on the therapeutic setting, raises ethical concerns. Some therapists have exploited this vulnerability in the past. To ensure valid informed consent, patients must be well informed about these mechanisms and their implications. Additional security measures are needed to protect patients in current research and future mainstream medical settings.

The Hopkins-Oxford Psychedelics Ethics (HOPE) Working Group Consensus Statement

American Journal of Bioethics May 2, 2024 Edward Jacobs, B. Earp, Paul S. Appelbaum et al. 29 citations

A workshop on psychedelic ethics, the first Hopkins-Oxford Psychedelic Ethics (HOPE) meeting, was held in August 2023 at the University of Oxford to address ethical issues surrounding psychedelics. The organizers (BDE, DBY, EJ) aimed to foster interdisciplinary discussion on topics such as informed consent, therapeutic use, and societal implications. The report outlines the workshop's structure, key themes, and proposed guidelines for ethical research and practice in the field.

Giving consent to the ineffable

Neuroethics February 15, 2024 Daniel Villiger 26 citations

The transformative nature of psychedelic-assisted therapy raises an ethical question about whether patients can give informed consent, because they cannot fully anticipate the experience. This paper argues that patients often have sufficient knowledge to consent, as they know they want to change their negative status quo and that the therapy offers an effective way to do so. Even without anticipating the specific manifestation of a psychedelic experience, patients can understand what the transformative nature means for them and make a value-aligned choice.

How Psychedelic-Assisted Treatment Works in the Bayesian Brain

Frontiers in Psychiatry March 8, 2022 Daniel Villiger 17 citations

Psychedelics are experiencing a renaissance in clinical research, with promising results for psychedelic-assisted treatment. This paper provides the first account of how pharmacological and psychological effects interact in such therapy. Building on the REBUS hypothesis and the contextual model, it argues that psychedelics amplify common factors of psychotherapy, particularly by attenuating the precision of high-level predictions, making them more revisable by bottom-up input. Psychotherapy provides a safe environment and remedial expectations, which become incorporated during prediction revision—a process reinforced and accelerated by psychedelics, ultimately leading to symptom relief.

How to make psychedelic-assisted therapy safer

Cambridge Quarterly of Healthcare Ethics September 27, 2024 Daniel Villiger 10 citations

Classic serotonergic psychedelics are seeing renewed clinical use, reviving ethical debates about patient vulnerability during psychedelic-assisted therapy. This vulnerability stems from impaired autonomy: psychedelics diminish decision-making capacity, reduce controllability, and limit resistance to external influences. The paper analyzes five proposed safety measures, finding preparatory sessions, advance directives, and specific training and oversight useful, while starting with a lower dosage and no therapy is less effective. It then introduces an overlooked but potentially highly effective and feasible safety measure: bringing a close person to the psychedelic session.

Mitigating Ethical Issues in Training for Psychedelic Therapy

Neuroethics April 1, 2025 Christopher Poppe, Daniel Villiger, Dimitris Repantis et al. 9 citations

Ethical problems in training for psychedelic therapy include the need for comprehensive training due to participant vulnerability, reliance on psychedelic experience without psychotherapeutic training, self-disclosure of personal psychedelic use, and guruism. Mitigation strategies include ethics codes and training, monitoring and control via video recording, requiring professional licensure and psychotherapy training for practitioners, and imposing a cooling-off period after therapists' personal psychedelic experiences to avoid a 'honeymoon' effect.

Same Same but Different: On Psychedelic Exceptionalism

American Journal of Bioethics January 1, 2025 Daniel Villiger 7 citations

The paper argues that the unusual features of psychedelic treatments—such as their subjective, mystical-like experiences—do not make them exceptional within medicine, and therefore they should not be granted exceptional ethical or regulatory status. The authors contend that many standard medical treatments also involve profound, subjective, or transformative experiences, and that singling out psychedelics as exceptional is inconsistent. Instead, they suggest that psychedelic treatments should be evaluated using the same ethical and regulatory frameworks applied to other medical interventions, without special exemptions.

Patient-therapist relationship in psychedelic-assisted therapy: Implications for future real-world settings.

General hospital psychiatry June 6, 2025 Daniel Villiger 4 citations

Questioning the necessity of embedding psychedelic use in psychotherapy, this paper examines cost pressures that could limit access to psychedelic-assisted therapy (PAT). It reviews evidence for the therapeutic and ethical importance of the patient-therapist relationship in PAT, then argues that shortening the preparation phase—a likely cost-saving measure—risks weakening that relationship. Three strategies are proposed to preserve the therapeutic bond under financial constraints: retaining relational elements during preparation, ensuring the same therapist works across all phases, and, when feasible, involving the patient's regular therapist.

Psychedelics beyond medicine: Treatment, enhancement, hype, consent, and the limits of medicalization

Philosophical Psychology September 8, 2025 Mina Caraccio, Katherine Cheung, Sebastian Porsdam Mann et al. 3 citations

As interest in psychedelics like psilocybin, ketamine, and MDMA revives and their legal status changes in many places, ethical guidelines are urgently needed for both medical and non-medical use. This paper argues that focusing only on medical applications neglects potentially valuable uses in other contexts and raises ethical issues including hype, exceptionalism, informed consent, therapeutic touch, data collection, and balancing access with safety. The authors call for renewed attention to the treatment-versus-enhancement distinction from bioethics and stress that guidelines should be flexible and context-sensitive. They recommend incorporating diverse stakeholder perspectives and cross-sector collaboration in future research and policy for psychedelic bioethics.

Mental disorder and its treatment as a transformative experience

Phenomenology and the Cognitive Sciences February 8, 2025 Daniel Villiger 1 citation

Developing a mental disorder like major depressive disorder typically involves a transformative experience: one that teaches something unlearnable without it and substantially changes a person's point of view. This explains why mentally disordered people are often misunderstood—their experiential state is epistemically inaccessible to those who have not undergone something similar. Successful treatment of such a disorder also requires a personally transformative experience that overcomes the disorder. Pharmacological, psychological, and psychedelic-assisted treatments each use a different transformative route to recovery, a finding relevant to debates in medical ethics about informed consent.

Mystical experience in the Bayesian brain

Phenomenology and the Cognitive Sciences December 10, 2025 Daniel Villiger

Mystical experiences, among the most profound human experiences, may arise from a specific neurocognitive state described by the REBUS hypothesis, originally developed to explain how psychedelics alter brain function. During a mystical experience, the brain reduces the influence of its high-level predictions while increasing the weight of sensory input. This shift explains key features: heightened sensory awareness produces a sense of deep knowing (noetic quality), while relaxed prior beliefs lead to feelings of oneness, altered time and space perception, ineffability, and positive mood. The account is conceptual and speculative but aligns with other models suggesting mystical experience involves maximal uncertainty or breakdown of attention.

The Double-Blind Randomized Controlled Trial as the Gold Standard in Psychedelic Research: Neither Feasible Nor Desirable.

Kennedy Institute of Ethics journal January 1, 2025 Daniel Villiger

Double-blind, randomized, controlled trials (DB-RCTs) are often considered the gold standard for establishing causal efficacy in medical research, but they face unique challenges when applied to psychedelic-assisted therapy (PAT). Participants can often guess whether they received a psychedelic due to its psychoactive effects, which may bias results through expectancy and experimenter behavior. This paper argues that the DB-RCT design should be abandoned as the assumed gold standard in PAT research because its logic is undermined by the intervention and it neglects important extrapharmacological factors. Instead, DB-RCTs should be seen as producing complementary, not superior, results to other research designs, allowing a more holistic study of PAT.