The relationship of the Brief Assessment of Cognition in Schizophrenia (BACS) to functional capacity and real-world functional outcome

Abstract

The Brief Assessment of Cognition in Schizophrenia (BACS) assesses five different domains of cognitive function with six tests, and takes about 30-35 minutes to complete in patients with schizophrenia. Previous work has demonstrated the reliability of this measure, and its sensitivity to the deficits of schizophrenia. However, the relationship of this brief cognitive measure to functional outcome has not been determined. Further, future registration trials for potentially cognitive enhancing compounds may not only assess efficacy with cognitive performance measures, but with assessments of real-world functional outcome and functional capacity. The purpose of this study was to determine the relationship between the BACS and a potential co-primary measure for treatment studies of cognition in schizophrenia, and to determine if such a measure accounts for significant variance in functioning beyond that provided by cognitive function. The current study assessed 60 patients with schizophrenia over the course of six months. Cognitive functions were measured with the BACS. Functional capacity was measured with the UCSD Performance-based Skills Assessment (UPSA). Real-world functional outcome was measured with the Independent Living Skills Inventory (ILSI). BACS composite scores were significantly correlated with functional capacity as measured by the UPSA (r = .65, df = 55, p < .001), and real-world functional outcome as assessed by the ILSI (r = .37, df = 56, p = .005). In multiple regression analyses, UPSA scores did not account for additional variance in real-world functioning beyond that accounted for by the BACS. These data suggest that brief cognitive assessments such as the BACS are able to assess aspects of cognition that are related to important functional measures in clinical trials of cognitive enhancement. They also suggest that the measures being considered as potential co-primary indicators of cognitive function for registration trials are significantly correlated with cognition as assessed by brief cognitive assessments.