title: Effects of different subanaesthetic doses of (S)-ketamine on psychopathology and binocular depth inversion in man.
abstract: The role of the N-methyl-D-aspartate (NMDA) neurotransmitter system in relation to psychoses is not completely understood, but represent a challenge in neurobiological research. The psychotic states induced by NMDA antagonists such as phencyclidine and ketamine have been described as being most similar to schizophrenia and the NMDA system has been implicated in the pathogenesis of schizophrenia. Binocular depth inversion, an illusion of visual perception, has been shown to be impaired in psychotic and psychotomimetic states in healthy and schizophrenic subjects. In this study, pictures of natural and artificial objects were presented stereoscopically to 12 healthy male volunteers and depth perception assessed using an operationalized method. The effects of the psychotomimetic S-enantiomer of the anaesthetic ketamine in two different subanaesthetic doses were compared with those of a placebo. In spite of dose dependence and grave subjective and significant objective psychopathology, no significant impairment of binocular depth perception was found with (S)-ketamine. Implications related to memory function, perceptogenesis and 'bottom-up' processing in ketamine model psychosis and schizophrenia are discussed.
authors.affiliation: Department of Clinical Psychiatry and Psychotherapy, Medical School Hannover, Hannover, Germany. dr.passie@gmx.de
authors.forename: Torsten
authors.initials: T
authors.lastname: Passie
authors.forename: Matthias
authors.initials: M
authors.lastname: Karst
authors.forename: Mathias
authors.initials: M
authors.lastname: Borsutzky
authors.forename: Birgitt
authors.initials: B
authors.lastname: Wiese
authors.forename: Hinderk M
authors.initials: HM
authors.lastname: Emrich
authors.forename: Udo
authors.initials: U
authors.lastname: Schneider
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D000778:Anesthetics, Dissociative / Q000008:administration & dosage / Q000009:adverse effects*; D000987:Antisocial Personality Disorder / Q000139:chemically induced / Q000523:psychology; D003867:Depth Perception / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D006801:Humans; D007262:Infusions, Intravenous; D007649:Ketamine / Q000008:administration & dosage / Q000009:adverse effects*; D008297:Male; D011569:Psychiatric Status Rating Scales; D013237:Stereoisomerism; D011795:Surveys and Questionnaires
chemical_list: D000778:Anesthetics, Dissociative; D007649:Ketamine