Moderator variables of executive functioning in schizophrenia: meta-analytic findings.
The literature regarding executive functioning in schizophrenia was examined to determine effect size differences between schizophrenic, normal control, and psychiatric groups. Effect sizes (n = 176) from 71 studies were cumulated across measures including the Wisconsin Card Sorting Test (WCST), Halstead Category Test (HCT), verbal/design fluency, Trail Making B (TMB), and the Stroop Color-Word Test. Schizophrenic groups were impaired relative to controls (delta = -1.45). Schizophrenic groups also performed 0.40 standard deviations lower than psychiatric groups. Within the schizophrenic versus normal control comparisons, the effect size based on complex measures, such as the WCST/HCT (delta = -1.42), was similar to that based on less complex measures, such as TMB and the Stroop (delta = -1.58). Chlorpromazine equivalents and illness duration were not significantly correlated with effect sizes (p > 0.05). Effect sizes and number of hospitalizations (p < 0.05) were related. Effect sizes and Brief Psychiatric Rating Scale (BPRS) were not significantly correlated. Negative and positive symptoms were significantly correlated (p < 0.05). The results as they apply to research and clinical practice are discussed.
Johnson-Selfridge
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Neuropsychology Service, San Francisco General Hospital, CA, USA. mtj@selfridge.com
Zalewski
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C
D000328:Adult; D003072:Cognition Disorders / Q000175:diagnosis* / Q000523:psychology; D005260:Female; D006801:Humans; D008297:Male; D009483:Neuropsychological Tests / Q000706:statistics & numerical data*; D011594:Psychometrics; D012016:Reference Values; D015203:Reproducibility of Results; D012559:Schizophrenia / Q000175:diagnosis*; D012565:Schizophrenic Psychology