Moderator variables of executive functioning in schizophrenia: meta-analytic findings

Schizophr Bull. 2001;27(2):305-16. doi: 10.1093/oxfordjournals.schbul.a006876.

Abstract

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.

Publication types

  • Meta-Analysis
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Cognition Disorders / diagnosis*
  • Cognition Disorders / psychology
  • Female
  • Humans
  • Male
  • Neuropsychological Tests / statistics & numerical data*
  • Psychometrics
  • Reference Values
  • Reproducibility of Results
  • Schizophrenia / diagnosis*
  • Schizophrenic Psychology*