Skip to content

Hannes Kettner

University of California, San Francisco, Leibniz Institute of Polymer Research

64 papers in the library · 2,790 citations · publishing 2018-2026

Papers

Validation of the Imperial Psychedelic Predictor Scale

PsyArXiv February 13, 2024 Michael Angyus, Sarah Osborn, Eline Haijen et al. 1 citation preprint

A new 9-item scale called the Imperial Psychedelic Predictor Scale (IPPS) predicts key features of the acute psychedelic experience. Analyzing four independent datasets (two online surveys with 741 and 836 participants, and two controlled administration studies with 30 and 28 participants), the scale showed good internal consistency and three factors: set, rapport, and intention. The IPPS significantly predicted mystical, challenging, and emotional breakthrough experiences. In one controlled dataset, set and rapport explained 40% of variance in mystical experience, and set alone explained 16% of variance in challenging experience. In another, rapport explained 9% of variance in emotional breakthrough. The scale may improve safety and therapeutic outcomes by forecasting response variability.

Psychedelics and Health Behavior Change - Journal of Psychopharmacology (in press)

March 24, 2021 Pedro J. Teixeira, Matthew W. Johnson, Christopher Timmermann et al. 1 citation preprint

Unhealthy behaviors like poor diet, inactivity, and smoking are major contributors to cancer, diabetes, and cardiovascular disease, causing substantial suffering and public health costs. Interventions to promote healthy behaviors increasingly draw on psychobiological models. This article explores the potential of psilocybin, a psychedelic with low toxicity and no addictive properties, to assist positive lifestyle change. Psilocybin has shown favorable effects in patients with depression, anxiety, and substance misuse, conditions marked by rigid behavioral patterns. The authors describe proposed mechanisms and research findings linking psychedelics to health behavior change, noting that therapeutic models combining psychedelic experiences with methods like Cognitive Behavior Therapy and Motivational Interviewing are already being tested for addiction and eating disorders. They suggest this research may extend to promoting diet, exercise, nature exposure, and mindfulness.

Correction to: Preliminary Evidence of Sleep Improvements Following Psilocybin Administration, and their Involvement in Antidepressant Therapeutic Action.

Curr Psychiatry Rep June 5, 2026 Matthew J. Reid, Hannes Kettner, Tessa F. Blanken et al. correction

A correction notice was issued for a previously published article on psilocybin administration and sleep improvements. The correction addresses errors in the original text but does not provide new findings or data.

On the meaning of ‘plasticity’ in neuroscience and mental health research and its relation to the action of psychedelic therapy

May 13, 2026 Robin Carhart-Harris, Richard Zeifman, Lorenzo Pasquini et al. preprint

The paper argues that the term 'plasticity' in neuroscience refers to induced changes in brain function or structure, which differs from the dictionary definition of plasticity as the ability to be shaped or molded. Many biomarkers of neuroplasticity actually index processes that bias phenotypic canalization, the opposite of phenotypic plasticity, creating a paradox. The authors question extrapolating from these biomarkers to improved mental health, as the relationship is context dependent. They propose a new construct, 'mediational and recalibrative plasticity' (MR-P), which aligns with plasticity proper and can describe and predict phenotypic changes relevant to mental health.

Effects of psychedelic use on authoritarian attitudes revisited.

Journal of psychopharmacology (Oxford, England) May 1, 2026 Otto Simonsson, Taylor Lyons, Joseph Marks et al.

Across three studies—a naturalistic observation, a single-arm psilocybin trial with healthy volunteers, and a randomized controlled trial comparing psilocybin to escitalopram in depressed patients—psychedelic use did not produce significant changes in authoritarian attitudes. Contrary to earlier suggestions, the evidence does not reliably show that psychedelics decrease authoritarian attitudes. Future work should use larger, more diverse samples and examine other political outcomes.

Observing the mind under psychedelics: conceptual metaphors used following four once-weekly macrodoses of psilocybin

Philosophical Psychology April 10, 2026 Eric Rundquist, Diego Nicolás Monasterio López, Juan Jonathan Oyarzo Alvarado et al.

A cognitive-linguistic analysis of interviews with a healthy volunteer after moderate-to-high psilocybin doses reveals that the participant consistently used metaphors framing abstract introspective events in terms of concrete, visible, and interpersonal events, instantiating a cognitive frame called the Observer's Model. These metaphors imply cognitive defusion and heightened metacognitive awareness during the sessions. Literal descriptions of hallucinatory visual experiences correlated semantically with metaphorical expressions, suggesting metaphorical thinking plays a role in motivating those experiences. The findings are linked to neuroscientific research on psychedelics and have psychological and therapeutic implications.

Baseline Mood and “Relational Triad” Predict Acute Qualities of Psychedelic Experience

Behavioral Sciences February 23, 2026 Joshua Lipson, Hannes Kettner, Robin Carhart-Harris et al.

Mood before taking a psychedelic substance and factors like social connectedness, mindfulness, and spirituality influence how the experience unfolds. People with higher baseline depression and anxiety tend to have more challenging experiences but not more mystical ones, while those with greater wellbeing report more mystical and fewer challenging experiences. Mindfulness and spirituality are linked to more mystical experiences, and social connectedness and mindfulness are linked to fewer challenging ones. Mystical and challenging experiences were weakly but positively correlated overall.

Exploring the potential psychological predictors associated with changes in depression, anxiety, and well-being following naturalistic psychedelic use.

Journal of psychiatric research November 1, 2025 Felipe M Herrmann, Grant Jones, Daniel M Low et al.

Increases in meaning in life, agreeableness, mindfulness, and extraversion are the psychological changes most strongly linked to future improvements in well-being after naturalistic psychedelic use. Increases in mindfulness, emotional stability, and extraversion are most associated with later reductions in anxiety, while increased self-esteem is most tied to decreased depression. Mindfulness was the only variable ranking among the top three predictors for all three outcomes—well-being, anxiety, and depression. These differing psychological changes may explain the mental health benefits observed after psychedelic use.

Human brain changes after first psilocybin use

October 14, 2024 Terence J. Lyons, Merle Spriggs, Leevi Kerkelä et al. preprint

A single high dose of psilocybin (25 mg) produced lasting functional and anatomical brain changes in healthy, psychedelic-naive adults, detected from one hour to one month later. Diffusion imaging showed decreased axial diffusivity in prefrontal-subcortical tracts, correlating with reduced brain network modularity, which in turn correlated with improved well-being. Increased cortical signal entropy shortly after dosing predicted better psychological well-being at one month, with next-day psychological insight mediating this relationship. No such effects occurred with a 1 mg placebo dose. Cognitive flexibility, psychological insight, and well-being also increased at one month.

Reply to Letter to the Editor: "Psychedelics in Older Adults: Difficulties of a Clear Therapeutic Evidence".

Am J Geriatr Psychiatry September 26, 2024 Hannes Kettner, Leor Roseman, Adam Gazzaley et al.

A reply to a letter to the editor addresses difficulties in establishing clear therapeutic evidence for psychedelics in older adults. The response likely discusses challenges such as study design, sample size, and confounding factors that complicate the interpretation of clinical data on psychedelic treatments for this population. It emphasizes the need for rigorous research to clarify the potential benefits and risks of psychedelic therapy in geriatric mental health care.

Observational cohort study of a group-based VR program to improve mental health and wellbeing in people with life-threatening illnesses

Joe Hardy, Hannes Kettner, David Glowacki et al. preprint

A group-based virtual reality program called Clear Light, delivered at home over three weeks, improved anxiety, depression, and wellbeing in people with life-threatening illnesses. The program included multi-user VR experiences, video calls, and text chats designed to elicit self-transcendent experiences similar to psychedelics. In a small observational study of 15 participants, moderate improvements were seen in anxiety, depression, wellbeing, demoralization, connectedness, and spiritual wellbeing. The intervention was well-tolerated. The findings suggest potential benefits but are limited by the lack of a comparison group, indicating the need for randomized controlled trials.

Ceremonial Psychedelic Experiences and Changes in Mental Health Outcomes in Those with Adverse Childhood Experiences

Psychedelic Medicine December 15, 2025 M. Mehmood, Rebecka Bremler, M. Spriggs et al.

People who experienced more adverse childhood experiences (ACEs) showed greater improvements in mental well-being, reductions in experiential avoidance, and lower trait anxiety after participating in psychedelic ceremonies compared to those with fewer ACEs. Higher ACE scores were also linked to stronger emotional breakthrough and mystical experiences during the psychedelic session. Among individuals with four or more ACEs, those who reported stronger mystical or emotional breakthrough experiences had better well-being at two and four weeks afterward, and mystical experiences were linked to less experiential avoidance while emotional breakthrough was linked to less anxiety at four weeks. However, the acute experiences did not significantly change how ACEs affected mental health outcomes overall.