Comparison of insight among schizophrenia and bipolar disorder patients in remission of affective and positive symptoms: analysis and critique.

Background: Schizophrenia and bipolar disorder are associated with impairments in insight, leading to a poorer clinical outcome and functioning. Earlier studies comparing the two disorders on the basis of insight included inpatients or patients who were clinically symptomatic. The current study therefore assessed patients in remission of affective symptoms and positive symptoms of schizophrenia.

Methods: Schizophrenia and bipolar disorder patients (n=32, n=34; respectively) underwent clinical and functional evaluations. Insight was assessed using the Scale to assess Unawareness of Mental Disorder (SUMD) and the positive and negative syndrome scale (PANSS). Attention was assessed using a continuous performance task (CANTAB's rapid visual information processing).

Results: Schizophrenia patients displayed poorer insight into having a mental disorder and into the social consequences thereof compared to the bipolar disorder patients. They were also less aware of their anhedonia-asociality. Age, however, was significantly correlated with insight and differences in insight between the patient groups became nonsignificant when age was used as a covariate in the statistical analyses. Age was not a moderating variable of the relationship between diagnosis and insight.

Conclusions: Significant differences in insight held by the two patient groups might be related to age disparities between patient groups. Earlier studies did not adequately address these age differences, their cause and their potential effects on findings. These issues are explored with regard to the findings of the current study, as well as earlier studies, emphasizing the need for further research of the relationship between age and insight.