Background : One factor contributing to impaired awareness of illness (poor insight) in psychotic disorders may be neurocognitive deficits.
Method : A systematic review and meta-analysis were conducted after data extraction. Following an overall analysis, in which measures of different cognitive domains were taken together, more fine-grained analyses investigated whether there was a specific relation with frontal executive functioning, and whether this was influenced by diagnosis or the insight scales used.
Results : There was a significant mean correlation between insight ratings and neurocognitive performance (mean weighted r=0.17, 95% CI 0.13-0.21, z=8.3, P<0.0001), based on 35 studies with a total of 2354 individuals. Further analyses revealed that the effect of general intellectual impairment was smaller than the specific association with executive function. This was only the case for psychosis in general, and not in an analysis limited to schizophrenia, where all cognitive domains were associated with impaired insight to a similar degree.
Conclusions : Neuropsychological dysfunction, specifically impairment of set-shifting and error monitoring, contributes to poor insight in psychosis. Specific relations with different dimensions of insight and the putative role of metacognitive functions require further study.