Disease, deficit or denial? Models of poor insight in psychosis

Objective: To examine the evidence for the three kinds of aetiological model that dominate the current literature on poor insight in psychosis: clinical models, the neuropsychological model, and the psychological denial model.

Method: Studies pertaining to one or more of these aetiological models were identified, reviewed and critically evaluated.

Results: There is little support for clinical models, partly because they lack testable hypotheses. Several studies reveal a positive relationship between insight and executive function, which may be related to frontal lobe dysfunction. However, the extent to which this relationship is specific and independent of general cognitive impairment remains unclear. There is tentative evidence to support the psychological denial model. Recent data combining the latter two approaches suggest that multiple factors contribute to poor insight.

Conclusion: Integration of different aetiological models is necessary for a fuller understanding of insight in psychosis. Future research should assess multiple aetiological mechanisms in single investigations.