title: A randomised, double-blind, placebo-controlled trial of tropisetron in patients with schizophrenia.
abstract: BACKGROUND
  Cognitive deficits in schizophrenia are associated with psychosocial deficits that are primarily responsible for the poor long-term outcome of this disease. Auditory sensory gating P50 deficits are correlated with neuropsychological deficits in attention, one of the principal cognitive disturbances in schizophrenia. Our studies suggest that the alpha7 nicotinic acetylcholine receptor (alpha7 nAChR) agonist tropisetron might be a potential therapeutic drug for cognitive deficits in schizophrenia. Therefore, it is of particular interest to investigate the effects of tropisetron on the cognitive deficits in patients with schizophrenia.
  
  
  METHODS
  A randomised, placebo-controlled trial of tropisetron in patients with schizophrenia was performed. A total of 40 patients with chronic schizophrenia who had taken risperidone (2 to 6 mg/day) were enrolled. Subjects were randomly assigned to a fixed titration of tropisetron (n = 20, 10 mg/day) or placebo (n = 20) in an 8-week double-blind trial. Auditory sensory gating P50 deficits and Quality of Life Scale (QLS), Cambridge Neuropsychological Test Automated Battery (CANTAB), and Positive and Negative Syndrome Scale (PANSS) scores were measured.
  
  
  RESULTS
  In all, 33 patients completed the trial. Tropisetron was well tolerated. Administration of tropisetron, but not placebo, significantly improved auditory sensory gating P50 deficits in non-smoking patients with schizophrenia. The score on the rapid visual information processing (sustained visual attention) task of CANTAB was significantly improved by tropisetron treatment. Total and subscale scores of PANSS were not changed by this trial. QLS scores in the all patients, but not non-smoking patients, were significantly improved by tropisetron trial.
  
  
  CONCLUSIONS
  This first randomised, double-blind, placebo-controlled trial supports the safety and efficacy of adjunctive tropisetron for treatment of cognitive deficits in schizophrenia.
authors.affiliation: Division of Clinical Neuroscience, Chiba University Center for Forensic Mental Health, Chiba, Japan. hashimoto@faculty.chiba-u.jp.
authors.forename: Akihiro
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authors.lastname: Shiina
authors.forename: Yukihiko
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authors.lastname: Shirayama
authors.forename: Tomihisa
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authors.lastname: Niitsu
authors.forename: Tasuku
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authors.lastname: Hashimoto
authors.forename: Taisuke
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authors.lastname: Yoshida
authors.forename: Tadashi
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authors.lastname: Hasegawa
authors.forename: Tadashi
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authors.lastname: Haraguchi
authors.forename: Nobuhisa
authors.initials: N
authors.lastname: Kanahara
authors.forename: Tetsuya
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authors.lastname: Shiraishi
authors.forename: Mihisa
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authors.lastname: Fujisaki
authors.forename: Goro
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authors.lastname: Fukami
authors.forename: Michiko
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authors.lastname: Nakazato
authors.forename: Masaomi
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authors.lastname: Iyo
authors.forename: Kenji
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authors.lastname: Hashimoto