Insight and prefrontal cortex in first-episode Schizophrenia

Few studies have investigated the neurobiological basis of impaired insight in antipsychotic-naive schizophrenia. However, the relationship between insight and specific prefrontally mediated cognitive functions suggests that insight deficits may be an expression of prefrontal cortical dysfunction. This study was designed to examine the relationship among insight, neurocognition, and dorsolateral prefrontal cortex (DLPFC) volumes in first-episode antipsychotic-naive schizophrenia subjects. DLPFC volumes were compared between 35 first-episode schizophrenia subjects with good (n = 17) and poor insight (n = 18). Morphometric measurements were based on MRI scans by trained raters blind to clinical information. First-episode schizophrenia subjects with poor insight showed decreased right DLPFC volumes relative to those with good insight. In addition, those with poor insight had higher levels of perseverative errors (PEs) on the Wisconsin Card Sort Test (WCST). No differences in other neuropsychological measures were found between the good and poor insight groups. Similarly, no differences were found between schizophrenia subjects with good versus poor insight on any of the psychopathological measures employed in this study. These findings suggest that poor insight in schizophrenia may be a function of specific prefrontally mediated neurocognitive deficits rather than a global impairment in neuropsychological functioning or different profiles of psychopathology.