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Erich Seifritz

University of Zurich, University Hospital Zurich

60 papers in the library · 3,650 citations · publishing 2011-2026

Papers

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Esketamine for treatment-resistant depression: Comparing two maintenance schedules in an observational real-world study

Research Square July 9, 2026 Samuel Westenhöfer, Yamina Ehrt, Barbora Provaznikova et al.

Abstract Background : Treatment-resistant depression (TRD) is associated with substantial clinical and socioeconomic burden. Intranasal esketamine has shown efficacy for TRD in clinical trials and real-world studies. However, evidence on optimal maintenance scheduling is limited. We therefore investigated whether two maintenance schedules differing in their inter-dose intervals were associated...

Ketamine-assisted psychotherapy for posttraumatic stress disorder: a systematic review and individual participant data meta-analysis of predictors of treatment effects.

Psychotherapy and Psychosomatics June 19, 2026 Judith Rohde, Tyler M Moore, Kathryn Walker et al.

Ketamine combined with psychotherapy has shown promise in treating posttraumatic stress disorder (PTSD), but predictors of clinical benefit remain unclear. In this systematic review and individual participant data meta-analysis (IPDMA), we examined patient- and treatment-level predictors of PTSD symptom change after combined treatment. Eligible studies combined ketamine with psychotherapy in...

Real-World Psilocybin Therapy for Treatment-Resistant Depression: a Retrospective Observational Study

December 10, 2025 Johannes Jungwirth, Samuel Westenhöfer, Helena Aicher et al.

Abstract Psilocybin has demonstrated promising antidepressant effects in depression and treatment-resistant depression (TRD) in controlled clinical trials. However, its effectiveness and safety in real-world therapeutic settings remain largely unknown. Although psilocybin is not yet approved as an antidepressant treatment, Switzerland’s unique legal framework allows its limited medical use for...

The role of frontal EEG in predicting clinical response of major depressive disorder to intranasal ketamine and esketamine.

Journal of Affective Disorders November 22, 2025 Carlos Trenado, Erich Seifritz, Sebastian Olbrich et al. 4 citations

Ketamine and its enantiomer esketamine are NMDA receptor antagonists that have shown consistent antidepressant effects in major depression disorder (MDD). These effects suggest an active role of glutamate in the pathophysiology of depression. It has been hypothesized that acute increase of glutamate neurotransmission in the prefrontal cortex following treatment with (es)ketamine leads to...

Memory deficits of MDMA users are linked to cortical thinning related to 5-HT receptor densities

Brain October 19, 2025 Rebecca C Coray, Vincent Beliveau, Josua Zimmermann et al. 1 citation

Regular recreational use of 3,4-methylenedioxymethamphetamine (MDMA, "Ecstasy") has been consistently linked to verbal memory dysfunctions, whose neurobiological origins remain unclear. Although neurochemical, structural, and functional alterations resulting from repeated MDMA intake have been identified in user populations, only limited knowledge exists regarding potential interrelationships...

Meditation, psychedelics, and brain connectivity: A randomized controlled resting-state fMRI study of N,N-dimethyltryptamine and harmine in a meditation retreat.

Imaging Neurosci (Camb) September 29, 2025 Klemens Egger, Daniel Meling, Firuze Polat et al. 1 citation

Meditation, psychedelics, and brain connectivity: A randomized controlled resting-state fMRI study of N,N-dimethyltryptamine and harmine in a meditation retreat.

Meditation, psychedelics, and brain connectivity: A randomized controlled resting-state fMRI study of N,N-dimethyltryptamine and harmine in a meditation retreat

Universität Zürich, ZORA September 29, 2025 Klemens Egger, Daniel Meling, Firuze Polat et al.

Both meditation and psychedelics are widely studied for their therapeutic potential in mental health. Recent research suggests potential synergies between mindfulness practice and psychedelics, though empirical studies have primarily focused on psilocybin. This study investigates the distinct and combined effects of mindfulness practice and an ayahuasca-inspired formulation containing...

The boon and bane of nitrous oxide.

European Archives of Psychiatry and Clinical Neuroscience September 1, 2025 Golo Kronenberg, Georgios Schoretsanitis, Erich Seifritz et al.

Nitrous oxide (N2O) has been known since the end of the eighteenth century. Today, N2O plays a huge role as a greenhouse gas and an ozone-depleting stratospheric molecule. The main sources of anthropogenic N2O emissions are agriculture, fuel combustion, wastewater treatment, and various industrial processes. By contrast, the contribution of medical N2O to the greenhouse effect appears to be...

Inhalational nitrous oxide as a transdiagnostic approach for the treatment of suicidal ideation and suicidality in psychiatric inpatients: protocol for a double-blind randomised, controlled clinical single-centre trial.

BMJ Open July 16, 2025 Golo Kronenberg, Anna Bankwitz, Barbora Provaznikova et al.

Suicidal thoughts and behaviours are linked to a wide range of mental health conditions. New interest in the psychiatric benefits of nitrous oxide (N2O) has only recently emerged. The broad pharmacological effects of N2O are thought to be due in large part to N-methyl-d-aspartate antagonism and opioid effects. The purpose of this study protocol is to test whether inhalational N2O exerts rapid...

EEG vigilance and response to oral prolonged-release ketamine in treatment-resistant depression - A double-blind randomized validation study.

Psychiatry research. Neuroimaging July 1, 2025 Anna Monn, Corinne Eicher, Annia Rüesch et al. 2 citations

Treatment-resistant depression (TRD) is associated with reduced quality of life and elevated mortality, posing a major challenge to psychiatric care. After non-response to conventional treatments, next-level interventions such as (es)ketamine are recommended, though remission rates remain variable. Identifying reliable markers of treatment response is therefore critical. Recent evidence...

Examining the pharmacokinetic and pharmacodynamic interaction of N,N-dimethyltryptamine and harmine in healthy volunteers: Α factorial dose-escalation study.

Biomedicine & pharmacotherapy = Biomedecine & pharmacotherapie March 1, 2025 Klemens Egger, Javier Jareño Redondo, Jovin Müller et al. 14 citations

Ayahuasca, a traditional psychoactive Amazonian brew, usually contains N,N-dimethyltryptamine (DMT) and β-carboline (harmine, harmaline, tetrahydroharmine) monoamine oxidase inhibitors. However, the pharmacological interactions between these compounds remain incompletely understood. In this study, we developed an ayahuasca-inspired formulation containing DMT and harmine, aiming to...

Pharmacokinetics and pharmacodynamics of an innovative psychedelic N,N-dimethyltryptamine/harmine formulation in healthy participants: a randomized controlled trial.

The International Journal of Neuropsychopharmacology December 28, 2024 Michael J Mueller, Helena Aicher, Dario Dornbierer et al. 10 citations

Recent interest in the clinical use of psychedelics has highlighted plant-derived medicines like ayahuasca showing rapid-acting and sustainable therapeutic effects in various psychiatric conditions. This traditional Amazonian plant decoction contains N,N-dimethyltryptamine (DMT) and β-carboline alkaloids such as harmine. However, its use is often accompanied by distressing effects like nausea,...

Combined Effects of Nasal Ketamine and Trauma-Focused Psychotherapy in Treatment-Resistant Post-Traumatic Stress Disorder: A Pilot Case Series.

Behavioral sciences (Basel, Switzerland) August 16, 2024 Judith Rohde, Elena Hickmann, Marco Buchmann et al. 7 citations

This pilot case series investigated the feasibility and efficacy of an eight-week therapy program, combining nasally administered ketamine (0.5 mg/kg) with trauma-focused psychotherapy, for individuals with chronic, treatment-resistant post-traumatic stress disorder (PTSD). Three patients with chronic, treatment-resistant PTSD underwent the eight-week therapy program. Clinical assessments...

The influence of psilocybin on subconscious and conscious emotional learning

iScience May 19, 2024 Andres Ort, John W Smallridge, Erich Seifritz et al. 1 citation

Serotonergic psychedelics hold promise as a treatment modality for various psychiatric disorders and are currently applied in psychedelic-assisted psychotherapy. We investigated the learning effects of the serotonin receptor agonist psilocybin in a probabilistic cue-reward task with emotional cues in the form of neutral or fearful faces, presented either consciously or subconsciously. This...

Oral prolonged-release ketamine in treatment-resistant depression - A double-blind randomized placebo-controlled multicentre trial of KET01, a novel ketamine formulation - Clinical and safety results.

Journal of Psychiatric Research May 1, 2024 Michael Colla, Benjamin Offenhammer, Hanne Scheerer et al. 23 citations

We investigated the antidepressant effects of a novel oral prolonged-release formulation of racemic ketamine (KET01) in patients suffering from treatment-resistant depression (TRD) as add-on therapy. Patients were randomized to an additional 160 mg/day or 240 mg/day KET01 or placebo for 14 days. The primary endpoint was change in Montgomery-Åsberg Depression Rating Scale (MADRS) scores from...

Ketamine induces multiple individually distinct whole-brain functional connectivity signatures.

Elife April 17, 2024 Flora Moujaes, Jie Lisa Ji, Masih Rahmati et al. 23 citations

Ketamine has emerged as one of the most promising therapies for treatment-resistant depression. However, inter-individual variability in response to ketamine is still not well understood and it is unclear how ketamine's molecular mechanisms connect to its neural and behavioral effects. We conducted a single-blind placebo-controlled study, with participants blinded to their treatment condition....

Psilocybin enhances insightfulness in meditation: a perspective on the global topology of brain imaging during meditation.

Scientific Reports March 26, 2024 Berit Singer, Daniel Meling, Matthias Hirsch-Hoffmann et al. 15 citations

In this study, for the first time, we explored a dataset of functional magnetic resonance images collected during focused attention and open monitoring meditation before and after a five-day psilocybin-assisted meditation retreat using a recently established approach, based on the Mapper algorithm from topological data analysis. After generating subject-specific maps for two groups (psilocybin...

Investigating functional brain connectivity patterns associated with two hypnotic states

Frontiers in Human Neuroscience December 19, 2023 Nuno M.p. de Matos, Philipp Staempfli, Erich Seifritz et al. 8 citations

While there's been clinical success and growing research interest in hypnosis, neurobiological underpinnings induced by hypnosis remain unclear. In this fMRI study (which is part of a larger hypnosis project) with 50 hypnosis-experienced participants, we analyzed neural and physiological responses during two hypnosis states, comparing them to non-hypnotic control conditions and to each other....

Comparing Neural Correlates of Consciousness: From Psychedelics to Hypnosis and Meditation

Biological Psychiatry Cognitive Neuroscience and Neuroimaging July 17, 2023 Flora Moujaes, Nathalie M. Rieser, Christophe Phillips et al. 19 citations

BACKGROUND: Pharmacological and nonpharmacological methods of inducing altered states of consciousness (ASCs) are becoming increasingly relevant in the treatment of psychiatric disorders. While comparisons between them are often drawn, to date no study has directly compared their neural correlates. METHODS: To address this knowledge gap, we directly compared 2 pharmacological methods...

TMS-EEG and resting-state EEG applied to altered states of consciousness: oscillations, complexity, and phenomenology.

iScience May 19, 2023 Andres Ort, John W Smallridge, Simone Sarasso et al. 47 citations

Exploring the neurobiology of the profound changes in consciousness induced by classical psychedelic drugs may require novel neuroimaging methods. Serotonergic psychedelic drugs such as psilocybin produce states of increased sensory-emotional awareness and arousal, accompanied by increased spontaneous electroencephalographic (EEG) signal diversity. By directly stimulating cortical tissue, the...

Single-dose psilocybin-assisted therapy in major depressive disorder: A placebo-controlled, double-blind, randomised clinical trial.

EClinicalMedicine February 1, 2023 Robin von Rotz, Eva M Schindowski, Johannes Jungwirth et al. 345 citations

Psilocybin has been suggested as a novel, rapid-acting treatment for depression. Two consecutive doses have been shown to markedly decrease symptom severity in an open-label setting or when compared to a waiting list group. To date, to our knowledge, no other trial compared a single, moderate dose of psilocybin to a placebo condition. In this double-blind, randomised clinical trial, 52...

Corrigendum to 'Single-dose psilocybin-assisted therapy in major depressive disorder: a placebo-controlled, double-blind, randomised clinical trial'.

EClinicalMedicine February 1, 2023 Robin von Rotz, Eva M Schindowski, Johannes Jungwirth et al. 8 citations correction

We wish to provide a correction of the colour representation of Fig. 2 in order to harmonise the colours representing the Psilocybin and the Placebo condition with the corresponding figure caption and with the colour codes from all other figures across the manuscript. Fig. 2 now depicts the Psilocybin condition in blue and the Placebo condition in yellow. The error occurred as a result of an...

Overcoming the clinical challenges of traditional ayahuasca: a first-in-human trial exploring novel routes of administration of N,N-Dimethyltryptamine and harmine.

Frontiers in Pharmacology 2023 Dario Dornbierer, Laurenz Marten, Jovin Mueller et al. 32 citations

Recently, the Amazonian plant medicine "ayahuasca"-containing the psychedelic compound N,N-dimethyltryptamine (DMT) and numerous β-carboline alkaloids, such as harmine-has been suggested to exhibit beneficial effects in patients with affective and other mental health disorders. Although ayahuasca ingestion is considered safe, its pharmacokinetics/pharmacodynamics and tolerability profile pose...