Clinical and neuropsychological correlates of insight in schizophrenia and bipolar I disorder: does diagnosis matter?

Abstract

BACKGROUND: Lack of insight is a well-recognized feature of schizophrenia and is associated with symptom severity and cognitive impairments. However, the diagnostic specificity of insight variables and their correlates is not known. To assess this specificity, we compared awareness of illness and neuropsychological function between patients with chronic schizophrenia and bipolar I disorder. METHOD: We assessed insight, level of psychopathology, and cognitive performance on a neuropsychological test battery in 37 patients with Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition bipolar I disorder, 32 patients with schizophrenia, and 31 healthy subjects for comparison. RESULTS: There was no significant difference between the 2 diagnostic groups on general illness awareness. However, patients with bipolar disorder had better awareness of their symptoms and their pathologic nature compared to patients with schizophrenia. Similar patterns of association emerged between insight and clinical variables. General unawareness was associated with clinical severity, especially of the affective type, and working memory deficits (Wechsler Adult Intelligence Scale digit span) in both diagnostic groups. The contribution of other cognitive deficits to insight differed across the groups. Misattribution differed from the other aspects of insight in its relative independence of clinical and neurocognitive correlates. Both patient groups were neurocognitively impaired, with the schizophrenia group performing significantly worse on conceptual ability, verbal learning, visuospatial processing, and motor speed. CONCLUSIONS: The results suggest that differences in general insight in major mental disorders may be explained by symptom severity and working memory function rather than the specific diagnosis. Subcomponents of insight are influenced by different factors emphasizing the need to consider insight as multidimensional.