OPEN Foundation

B. Wiese

Effects of different subanesthetic doses of (S)-ketamine on neuropsychology, psychopathology, and state of consciousness in man

May 12, 2005 / Ketamine, Other subjects, Papers, Psychiatry, Psychology, Psychopharmacology, Publications / By / , , , ,

Abstract

This is the first neuropsychological study using the S-enantiomer of the noncompetetive N-methyl-D-aspartate antagonist ketamine. In 2 randomized placebo-controlled trials we studied effects of two different doses of (S)-ketamine (low dose/high dose) on neuropsychological functions and psychopathology in 12 healthy male volunteers. Impairment was measured via standardized neuropsychological tests. Results indicate that both subanaesthetic doses produce only nonsignificant impair ment in most of the tasks. Tasks involving divided and sustained attention as well as scores for objective and subjective psychopathology show significant impairment in a dose-dependent manner. Implications of these findings for the neuropsychology of attention and schizophrenia are discussed.

Passie, T., Karst, M., Wiese, B., Emrich, H. M., & Schneider, U. (2005). Effects of different subanesthetic doses of (S)-ketamine on neuropsychology, psychopathology, and state of consciousness in man. Neuropsychobiology, 51(4), 226-233. http://dx.doi.org/10.1159%2F000085724
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Effects of different subanaesthetic doses of (S)-ketamine on psychopathology and binocular depth inversion in man

January 1, 2003 / Ketamine, Papers, Psychiatry, Psychology, Psychopharmacology, Psychosis, Publications / By / , , , , ,

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.

Passie, T., Karst, M., Borsutzky, M., Wiese, B., Emrich, H. M., & Schneider, U. (2003). Effects of different subanaesthetic doses of (S)-ketamine on psychopathology and binocular depth inversion in man. Journal of Psychopharmacology, 17(1), 51-56. http://dx.doi.org/10.1177/0269881103017001698
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30 April - Q&A with Rick Strassman

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