Failures of metacognition and lack of insight in neuropsychiatric disorders

Abstract

Lack of insight or unawareness of illness is the hallmark of many psychiatric disorders, especially schizophrenia (SCZ) and other psychoses, and could be conceived of as a failure in metacognition. Research in this area in the mental health field has burgeoned with the development and widespread use of standard assessment instruments and the mapping out of the clinical and neuropsychological correlates of insight and its loss. There has been a growing appreciation of the multifaceted nature of the concept and of the different objects of insight such as the general awareness that one is ill, to more specific metacognitive awareness of individual symptoms, impairments and performance. This in turn has led to the notion that insight may show modularity and may fractionate across different domains and disorders, supported by work which directly compares metacognition of memory deficits and illness awareness in patients with SCZ, Alzheimer's disease (AD) and brain injury (BI). The focus of this chapter will be on the varieties of metacognitive failure in psychiatry, particularly the psychoses. We explore cognitive models based on self-reflectiveness and their possible social and neurological bases including data from structural and functional MRI. The medial frontal cortex appears to play an important role in self-appraisal in health and disease.