Skip to content

Raphaël Gaillard

Université Paris Cité, Paris F-75006, France; Department of Psychiatry, Service Hospitalo-Universitaire, GHU Paris Psychiatry & Neurosciences, Paris F-75014, France; Institut Pasteur, Experimental Neuropathology Unit, Global Health Department, Paris, France.

4 papers in the library · 10 citations · publishing 2025-2026

Papers

Neurocognitive effects of psilocybin: A systematic and comprehensive review of neuroimaging studies in humans.

Neuroscience and biobehavioral reviews August 1, 2025 Lucie Berkovitch, Baptiste Fauvel, Katrin H Preller et al. 8 citations

Psilocybin, a psychedelic compound, shows fast-acting and sustainable efficacy for treating psychiatric disorders. A systematic review of 81 neuroimaging studies found that psilocybin reproducibly impacts brain networks, particularly the default mode network, though other findings were inconsistent. Effects include acute alterations in self-experience, sensory and emotional processing, and sustained changes in mood, personality, and social functioning. In patients with depression, clinical outcomes correlated with brain changes. The review indicates psilocybin induces acute and long-lasting functional brain changes, shedding light on mechanisms underlying its subjective and therapeutic effects.

Trauma re-experiencing episodes during esketamine treatment in patients with treatment-resistant depression and comorbid PTSD: a retrospective case series.

European journal of psychotraumatology December 1, 2026 Maud Rothärmel, Lila Mekaoui, François Kazour et al. 1 citation

In a retrospective study of 22 adults with treatment-resistant depression and comorbid post-traumatic stress disorder who received esketamine nasal spray, trauma re-experiencing episodes occurred during treatment sessions. For 16 patients (72.7%) these episodes disappeared as sessions progressed. Treatment was stopped for 6 patients (27.3%) due to re-experiencing. Among those who continued esketamine, depression response rate was 45.5% and remission 22.7%; PTSD improvement rate was 45.5% and remission 18.2%. The findings suggest esketamine can be safely administered in this comorbid population and that trauma re-experiencing does not prevent clinical improvement.

Mystical Experience Induced by Esketamine Treatment: A Real-World Observational Study

medRxiv Preprint Server March 31, 2026 Maia Mallevays, Louise Fuet, Michel Danon et al. 1 citation preprint

In patients with treatment-resistant depression receiving esketamine, mystical experiences—similar to those induced by classic psychedelics—occurred in 58% of patients, with high variability across sessions. Higher mean and peak scores on the Mystical Experience Questionnaire (MEQ-30) were associated with greater improvement in depression severity, while dissociative or other non-mystical effects were not. Positive mood and mystical dimensions of the MEQ predicted therapeutic outcomes, and baseline spirituality predicted both treatment response and peak MEQ scores in the first week. These findings suggest that psychedelic-like mystical experiences may contribute to esketamine's therapeutic efficacy.

Ketamine disrupts consciousness in healthy participants in relation with psychotic-like symptoms.

bioRxiv : the preprint server for biology November 8, 2025 Lucie Berkovitch, Alexandre Salvador, Thomas Andrillon et al. preprint

Low doses of ketamine, an NMDA-receptor antagonist, disrupt the ability to consciously perceive visual information in healthy people. In a double-blind, placebo-controlled experiment with 21 volunteers, ketamine increased visual masking and reduced conscious perception of a digit. The N1 component of brain activity, an early marker of visual processing, was significantly reduced under ketamine and correlated with conscious access. Ketamine also induced psychotic-like and manic-like symptoms, but only the psychotic-like dimension was linked to impairments in conscious access. These findings suggest ketamine attenuates early visual brain responses, impairing conscious access, and that this mechanism differs in some ways from that seen in schizophrenia.