title: Antipsychotic medication and cognitive function in schizophrenia.
abstract: Antipsychotic polypharmacy and excessive dosing still prevail worldwide in the treatment of schizophrenia, while their possible association with cognitive function has not well been examined. We examined whether the "non-standard" use of antipsychotics (defined as antipsychotic polypharmacy or dosage >1,000 mg/day of chlorpromazine equivalents) is associated with cognitive function. Furthermore, we compared cognitive function between patients taking only atypical antipsychotics and those taking only conventionals. Neurocognitive functions were assessed in 67 patients with chronic schizophrenia and 92 controls using the Wechsler Memory Scale-Revised (WMS-R), the Wechsler Adult Intelligence Scale-Revised (WAIS-R), the Wisconsin Card Sorting Test (WCST), and the Advanced Trail Making Test (ATMT). Patients showed markedly poorer performance than controls on all these tests. Patients on non-standard antipsychotic medication demonstrated poorer performance than those on standard medication on visual memory, delayed recall, performance IQ, and executive function. Patients taking atypical antipsychotics showed better performance than those taking conventionals on visual memory, delayed recall, and executive function. Clinical characteristics such as duration of medication, number of hospitalizations, and concomitant antiparkinsonian drugs were different between the treatment groups (both dichotomies of standard/non-standard and conventional/atypical). These results provide evidence for an association between antipsychotic medication and cognitive function. This association between antipsychotic medication and cognitive function may be due to differential illness severity (e.g., non-standard treatment for severely ill patients who have severe cognitive impairment). Alternatively, poorer cognitive function may be due in part to polypharmacy or excessive dosing. Further investigations are required to draw any conclusions.
authors.affiliation: Department of Mental Disorder Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Ogawahigashi, Kodaira, Tokyo, Japan. balius26@hotmail.com
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Hori
authors.forename: Hiroko
authors.initials: H
authors.lastname: Noguchi
authors.forename: Ryota
authors.initials: R
authors.lastname: Hashimoto
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Nakabayashi
authors.forename: Mayu
authors.initials: M
authors.lastname: Omori
authors.forename: Sho
authors.initials: S
authors.lastname: Takahashi
authors.forename: Ryotaro
authors.initials: R
authors.lastname: Tsukue
authors.forename: Kimitaka
authors.initials: K
authors.lastname: Anami
authors.forename: Naotsugu
authors.initials: N
authors.lastname: Hirabayashi
authors.forename: Seiichi
authors.initials: S
authors.lastname: Harada
authors.forename: Osamu
authors.initials: O
authors.lastname: Saitoh
authors.forename: Masao
authors.initials: M
authors.lastname: Iwase
authors.forename: Osami
authors.initials: O
authors.lastname: Kajimoto
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Takeda
authors.forename: Shigeo
authors.initials: S
authors.lastname: Okabe
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kunugi
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D014150:Antipsychotic Agents / Q000627:therapeutic use*; D003071:Cognition / Q000187:drug effects*; D005260:Female; D006801:Humans; D007361:Intelligence Tests / Q000706:statistics & numerical data; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests / Q000706:statistics & numerical data; D012559:Schizophrenia / Q000188:drug therapy*
chemical_list: D014150:Antipsychotic Agents