A meta-analysis of executive dysfunction in patients with schizophrenia: Different degree of impairment in the ecological subdomains of the Behavioural Assessment of the Dysexecutive Syndrome.

We performed meta-analyses of studies using the 6 subtests of the neuropsychological test battery, the Behavioural Assessment of the Dysexecutive Syndrome (BADS), in order to assess and compare subdomains of executive dysfunction in stable phase patients with schizophrenia relative to healthy controls. The meta-analyses were performed according to the PRISMA statement. A systematic literature search was performed yielding 10 studies for inclusion (NSCH = 375; NHC = 541). Meta-analyses were done using Stata IC 14. Due to large heterogeneity and the few number of studies a random-effects model was used along with Hedges' g. Results showed that relative to healthy controls, patients with schizophrenia overall performed significantly worse in all subtests of BADS. However, moderate effect sizes were seen with regard to temporal estimation and strategy-forming, while very large effect sizes were seen regarding complex forward planning, inhibition, cognitive flexibility and novel problem solving. The findings from this meta-analysis demonstrate a significant difference between patients with (primarily) longer lasting schizophrenia and healthy control subjects on all subdomains of executive functions (EF). But some aspects of EF seem to be more severely affected than others. Future research and clinical interventions need to differentiate between subdomains of EF.