Modification and validation of a performance-based functional capacity instrument for individuals with schizophrenia

Functional impairments are common in schizophrenia patients, but few performance-based instruments are available to evaluate their functional capacity, especially those that are culturally adapted for use in China. This study aimed to modify the items of the original Beijing Performance-based Functional Ecological Test (BJ-PERFECT) due to limited tasks in a particular scenario and examine the psychometric properties of the newly modified BJ-PERFECT in schizophrenia patients. Participants of the study comprised 105 schizophrenia patients and 45 healthy controls (HCs). All of them were administered the modified BJ-PERFECT, the University of California, San Diego, Performance-based Skill Assessment-Brief version (UPSA-B) and the Global Assessment of Functioning (GAF). The modified BJ-PERFECT retained seven original items and added 4 new items. The validity of the modified BJ-PERFECT was supported by its significant correlation with the UPSA-B but not the GAF and by the significant difference on the instrument's scores between the schizophrenia patients and HCs. The internal consistency reliability was found to be good. Level of education was found to have a significant relationship with functional capacity. The modified BJ-PERFECT was found to be psychometrically valid to assess functional capacity in schizophrenia patients.