Comparing the influences of age and disease on the Brief Assessment of Cognition in Schizophrenia in Japanese patients with schizophrenia.

Background: The Brief Assessment of Cognition in Schizophrenia (BACS) is an evaluation of cognitive function that can be completed with more cases. However, there are few studies that compare which factor, disease or aging, is a better determinant of performance on the BACS. The present study aimed to investigate the influences of disease and aging on BACS performance in schizophrenic patients using subjects with a wide range of ages.

Methods: Schizophrenic patients (n = 165) and a comparison group (n = 171) were recruited as subjects. All participants completed the Japanese language version of the BACS (BACS-J), and the influences of disease and aging on performance in the BACS were examined with the use of multiple regression analysis.

Results: There was a significant influence of diagnosis and level of education on all six tasks of the BACS and the performance and composite scores. In addition, age was found to influence five tasks and the composite score, the duration of illness influenced four tasks and the composite score, and gender influenced one task and the composite score.

Conclusion: The present study suggests that performance on the BACS was impaired not only by disease but also by level of education and aging.