Current Treatment Options in Psychiatry
November 11, 2025
Dan Petrovitch, Sarah E. Victor, André Schmidt et al.
2 citations
Abstract Purpose of Review This commentary summarizes how the intense and distinctive subjective effects of psychedelics complicate tests of the efficacy and mechanisms of action (MOAs) of psychedelic-assisted treatments (PATs) for mental-health conditions. Specifically, we discuss (a) how estimates of PAT efficacy are confounded under functional unblinding and (b) uncertainty surrounding...
Psychopharmacology
November 5, 2025
Milad Soltanzadeh, Wang Zheng, Shona G. Allohverdi et al.
1 citation
RationaleKetamine and psilocybin have demonstrated therapeutic potential for mental disorders, including major depressive disorder, yet they engage distinct mechanisms of action. Ketamine, a dissociative hallucinogen, acts by blocking N-methyl-D-aspartate receptors (NMDAR), whereas psilocybin primarily targets serotonin receptors. These divergent mechanisms are reflected in their...
Research Square
September 26, 2024
Shona G. Allohverdi, Milad Soltanzadeh, André Schmidt et al.
Abstract Ketamine and psilocybin show potential as therapies for various mental illnesses, including major depressive disorder. However, further investigation into their neural mechanisms is required to understand their effects on the brain. By combining computational modelling with electroencephalography (EEG), we examine the effects of ketamine and psilocybin on hierarchical sensory...
Journal of Neuroscience
June 19, 2020
Lilian Weber, Andreea O. Diaconescu, Christoph Mathys et al.
82 citations
The auditory mismatch negativity (MMN) is significantly reduced in schizophrenia. Notably, a similar MMN reduction can be achieved with NMDA receptor (NMDAR) antagonists. Both phenomena have been interpreted as reflecting an impairment of predictive coding or, more generally, the "Bayesian brain" notion that the brain continuously updates a hierarchical model to infer the causes of its sensory...
NeuroImage: Clinical
March 7, 2018
F. Müller, Patrick C. Dolder, André Schmidt et al.
187 citations
LSD is an ambiguous substance, said to mimic psychosis and to improve mental health in people suffering from anxiety and depression. Little is known about the neuronal correlates of altered states of consciousness induced by this substance. Limited previous studies indicated profound changes in functional connectivity of resting state networks after the administration of LSD. The current...
The International Journal of Neuropsychopharmacology
November 22, 2017
André Schmidt, Felix Müller, Patrick C. Dolder et al.
25 citations
Background: Stimulants such as methylphenidate and modafinil are frequently used as cognitive enhancers in healthy people, whereas 3,4-methylenedioxymethamphetamine (ecstasy) is proposed to enhance mood and empathy in healthy subjects. However, comparative data on the effects of methylphenidate and modafinil on negative emotions in healthy subjects have been partially missing. The aim of this...
Psychological Medicine
October 2, 2017
André Schmidt, Felix Müller, Claudia Lenz et al.
62 citations
Abstract Background Recent evidence shows that the serotonin 2A receptor (5-hydroxytryptamine2A receptor, 5-HT 2A R) is critically involved in the formation of visual hallucinations and cognitive impairments in lysergic acid diethylamide (LSD)-induced states and neuropsychiatric diseases. However, the interaction between 5-HT 2A R activation, cognitive impairments and visual hallucinations is...
Acta Psychiatrica Scandinavica
September 21, 2017
Felix Müller, Claudia Lenz, Patrick C. Dolder et al.
149 citations
Objective It has been proposed that the thalamocortical system is an important site of action of hallucinogenic drugs and an essential component of the neural correlates of consciousness. Hallucinogenic drugs such as LSD can be used to induce profoundly altered states of consciousness, and it is thus of interest to test the effects of these drugs on this system. Method 100 μg LSD was...
The International Journal of Neuropsychopharmacology
May 16, 2017
André Schmidt, Felix Müller, Patrick C. Dolder et al.
41 citations
Background: Psychostimulants such as methylphenidate and modafinil are increasingly used by healthy people for cognitive enhancement purposes, whereas the acute effect of 3,4-methylenedioxymethamphetamine (ecstasy) on cognitive functioning in healthy subjects remains unclear. This study directly compared the acute effects of methylphenidate, modafinil, and 3,4-methylenedioxymethamphetamine on...
NeuroImage Clinical
August 22, 2015
Rainer Kraehenmann, André Schmidt, Karl Friston et al.
107 citations
Stimulation of serotonergic neurotransmission by psilocybin has been shown to shift emotional biases away from negative towards positive stimuli. We have recently shown that reduced amygdala activity during threat processing might underlie psilocybin's effect on emotional processing. However, it is still not known whether psilocybin modulates bottom-up or top-down connectivity within the...
Current Pharmaceutical Design
May 10, 2014
Johannes Wrege, André Schmidt, Anna Walter et al.
96 citations
We conducted a systematic review to assess the evidence for specific effects of cannabis on impulsivity, disinhibition and motor control. The review had a specific focus on neuroimaging findings associated with acute and chronic use of the drug and covers literature published up until May 2012. Seventeen studies were identified, of which 13 met the inclusion criteria; three studies investigated...
Cerebral Cortex
July 16, 2013
Fosco Bernasconi, André Schmidt, Thomas Pokorny et al.
62 citations
Emotional face processing is critically modulated by the serotonergic system. For instance, emotional face processing is impaired by acute psilocybin administration, a serotonin (5-HT) 1A and 2A receptor agonist. However, the spatiotemporal brain mechanisms underlying these modulations are poorly understood. Here, we investigated the spatiotemporal brain dynamics underlying psilocybin-induced...
Journal of Neuroscience
June 19, 2013
Michael Kometer, André Schmidt, Lutz Jäncke et al.
357 citations
Visual illusions and hallucinations are hallmarks of serotonergic hallucinogen-induced altered states of consciousness. Although the serotonergic hallucinogen psilocybin activates multiple serotonin (5-HT) receptors, recent evidence suggests that activation of 5-HT2A receptors may lead to the formation of visual hallucinations by increasing cortical excitability and altering visual-evoked...
Cerebral Cortex
August 8, 2012
André Schmidt, Andreea O. Diaconescu, Michael Kometer et al.
110 citations
This paper presents a model-based investigation of mechanisms underlying the reduction of mismatch negativity (MMN) amplitudes under the NMDA-receptor antagonist ketamine. We applied dynamic causal modeling and Bayesian model selection to data from a recent ketamine study of the roving MMN paradigm, using a cross-over, double-blind, placebo-controlled design. Our modeling was guided by a...
Psychopharmacology
July 26, 2012
André Schmidt, Michael Kometer, Rosilla Bachmann et al.
94 citations
RationaleBoth glutamate and serotonin (5-HT) play a key role in the pathophysiology of emotional biases. Recent studies indicate that the glutamate N-methyl-D-aspartate (NMDA) receptor antagonist ketamine and the 5-HT receptor agonist psilocybin are implicated in emotion processing. However, as yet, no study has systematically compared their contribution to emotional biases.ObjectivesThis study...
Biological Psychiatry
May 9, 2012
Michael Kometer, André Schmidt, Rosilla Bachmann et al.
300 citations
BackgroundSerotonin (5-HT) 1A and 2A receptors have been associated with dysfunctional emotional processing biases in mood disorders. These receptors further predominantly mediate the subjective and behavioral effects of psilocybin and might be important for its recently suggested antidepressive effects. However, the effect of psilocybin on emotional processing biases and the specific...
Zurich Open Repository and Archive (University of Zurich)
2012
André Schmidt
Recent studies into the molecular, pharmacological and behavioral basis of psychotomimetics such as the glutamate N-methyl- D -aspartate receptor (NMDAR) antagonist ketamine and the mixed 5- hydroxytryptamine (5-HT) receptor agonist psilocybin in healthy human subjects suggest that both the glutamatergic and serotonergic system are implicated in the pathophysiolology of psychotic disorders such...