Neurocognitive function and insight in schizophrenia: support for an association with impairments in executive function but not with impairments in global function.

It remains unclear how impaired insight and neurocognitive impairment are related to one another in schizophrenia. In order to examine this relationship, subjects with schizophrenia or schizoaffective disorder were classified as having 'impaired' (n=38) or 'unimpaired' (n=43) insight based on their insight rating on the Positive and Negative Syndrome Scale (PANSS). Their performance on neuropsychological tests of global function, executive function, memory and vigilance was then compared. Multivariate analyses followed by Scheffe tests indicated that subjects with impaired insight performed less well on the Wisconsin Card Sorting Test, demonstrating poorer abstract flexibility and heightened perseveration. No differences were found between the groups with regard to global cognitive function, memory or vigilance. This suggests that insight is closely linked to deficits in executive function, and that it may be associated with the compromise of frontal lobe function.