Anosognosia in schizophrenia

Anosognosia, defined as a lack of knowledge of the disease, was originally identified in neurological disorders and is common in schizophrenia. These deficits are commonly referred to as "lack of insight" or "unawareness of illness." They include challenges in accurate judgments of the reality of experience, as well as global and specific personal abilities. Related to inaccuracies in self-assessment are response biases when an incorrect self-assessment is made. We adopted a perspective focused on Introspective Accuracy (IA) and Introspective Bias (IB). IA is the ability to accurately judge several domains of experience and functioning. These include the reality of clinical symptoms, the experience of mood states, momentary competence in the performance of cognitive assessments and everyday functional skills, and the ability to accurately anticipate the success of future performance. IB is the direction of response bias in the context of impairments in IA. Deficits in insight, judgment inaccuracies, and response bias are highly relevant as these difficulties come with downstream impacts including difficulties with treatment adherence, an increase in severity of symptoms, greater everyday disability, reduced response to cognitive training interventions, and a need for increased intensity of interventions to maintain community residence. In this article, we review the research in IA and IB in schizophrenia, including differences in momentary versus global self-assessments, and the clinical correlates and functional impacts of inaccurate self-assessments and response biases in the context of self-assessment errors. We also examine the existing data regarding the neurobiological basis of impairments in IA.