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Mismatch negativity encoding of prediction errors predicts S-ketamine-induced cognitive impairments.

André Schmidt, Rosilla Bachmann, Michael Kometer, Philipp A Csomor, Klaas E Stephan, Erich Seifritz, Franz X. Vollenweider

Neuropsychopharmacology March 2012 DOI: 10.1038/npp.2011.261 (opens in new tab)

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Study at a glance

AI-extracted from the abstract
Characteristics Double-blind within-subject placebo-controlled study Peer reviewed
Population Healthy subjects (volunteers)
Interventions S-ketamine psilocybin
Measures Altered States of Consciousness (ASC-R) questionnaire, mismatch negativity (MMN) memory trace effect
Topics Esketamine Ketamine
Key points S-ketamine, but not psilocybin, disrupted prediction-error processing as indexed by a frontally disrupted MMN memory trace effect. Both drugs induced positive-like symptoms, but prediction-error processing under placebo correlated significantly only with the severity of cognitive impairments induced by S-ketamine. The authors suggest the NMDAR system, not the 5-HT(2A)R system, is implicated in prediction-error processing during the MMN paradigm.

Abstract

Psychotomimetics like the N-methyl-D-aspartate receptor (NMDAR) antagonist ketamine and the 5-hydroxytryptamine2A receptor (5-HT(2A)R) agonist psilocybin induce psychotic symptoms in healthy volunteers that resemble those of schizophrenia. Recent theories of psychosis posit that aberrant encoding of prediction errors (PE) may underlie the expression of psychotic symptoms. This study used a roving mismatch negativity (MMN) paradigm to investigate whether the encoding of PE is affected by pharmacological manipulation of NMDAR or 5-HT(2A)R, and whether the encoding of PE under placebo can be used to predict drug-induced symptoms. Using a double-blind within-subject placebo-controlled design, S-ketamine and psilocybin, respectively, were administrated to two groups of healthy subjects. Psychological alterations were assessed using a revised version of the Altered States of Consciousness (ASC-R) questionnaire. As an index of PE, we computed changes in MMN amplitudes as a function of the number of preceding standards (MMN memory trace effect) during a roving paradigm. S-ketamine, but not psilocybin, disrupted PE processing as expressed by a frontally disrupted MMN memory trace effect. Although both drugs produced positive-like symptoms, the extent of PE processing under placebo only correlated significantly with the severity of cognitive impairments induced by S-ketamine. Our results suggest that the NMDAR, but not the 5-HT(2A)R system, is implicated in PE processing during the MMN paradigm, and that aberrant PE signaling may contribute to the formation of cognitive impairments. The assessment of the MMN memory trace in schizophrenia may allow detecting early phases of the illness and might also serve to assess the efficacy of novel pharmacological treatments, in particular of cognitive impairments.

Comparable studies

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Study Year Design Participants
Efficacy and Safety of Flexibly Dosed Esketamine Nasal Spray Combined With a Newly Initiated Oral Antidepressant in Treatment-Resistant Depression: A Randomized Double-Blind Active-Controlled Study Adults with moderate to severe nonpsychotic depression and a history of nonresponse to... 2019 Phase 3, double-blind, active-controlled, multicenter randomized controlled trial n = 227
Efficacy of Esketamine Nasal Spray Plus Oral Antidepressant Treatment for Relapse Prevention in Patients With Treatment-Resistant Depression Adults with treatment-resistant depression who achieved stable remission or stable... 2019 Phase 3, multicenter, double-blind, randomized withdrawal study n = 297
Efficacy and Safety of Intranasal Esketamine Adjunctive to Oral Antidepressant Therapy in Treatment-Resistant Depression Adults with DSM-IV-TR diagnosis of major depressive disorder and history of inadequate... 2017 Phase 2, double-blind, doubly randomized, delayed-start, placebo-controlled study n = 67
Efficacy and Safety of Intranasal Esketamine for the Rapid Reduction of Symptoms of Depression and Suicidality in Patients at Imminent Risk for Suicide: Results of a Double-Blind, Randomized, Placebo-Controlled Study Depressed patients at imminent risk for suicide 2018 Randomized controlled trial n = 68
Efficacy and Safety of Fixed-Dose Esketamine Nasal Spray Combined With a New Oral Antidepressant in Treatment-Resistant Depression: Results of a Randomized, Double-Blind, Active-Controlled Study (TRANSFORM-1) Adults with moderate-to-severe depression and nonresponse to at least two... 2019 Randomized controlled trial n = 346

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Esketamine Ketamine Altered states of consciousness Philosophy of mind Psilocybin Serotonin