Psychometric properties of the Chinese version of the Functioning Assessment Short Test (FAST) in bipolar disorder

Bipolar disorder (BD) is often associated with significant functional impairment. However, there is currently no valid and reliable instrument for this variable that is both brief and easy to administer in China. We thus aimed to evaluate the psychometric properties of the Chinese version of the Functioning Assessment Short Test (FAST) in Chinese adults with BD.

In this sample of adult subjects, 176 with BD and 53 healthy controls were included. The Chinese version of the FAST, the Young Mania Rating Scale (YMRS), the 17-item Hamilton Depression Rating Scale (HDRS-17) and the Global Assessment Functioning (GAF) were administered, and the psychometric analysis of the FAST was conducted.

The internal consistency (Cronbach's alpha) was 0.89 and 0.88 for the FAST at the baseline and week 1, respectively. Four domains (occupational functioning, cognitive functioning, interpersonal relationship and financial issues) at baseline had high item-total correlations. The FAST assessments at baseline and week 1 were highly correlated, indicating high test-retest reliability. The FAST total score was strongly associated with GAF total scores at week 0 (r  = -0.952, p < 0.001), HDRS (r = 0.575, p < 0.001) and YRMS (r = 0.394, p < 0.001) and at week 1 (r  = -0.945, p < 0.001; r  = 0.582, p < 0.001; r  = 0.363, p < 0.001), respectively, suggesting high concurrent validity. The FAST showed four dimensional measurement properties in exploratory factor analysis at baseline.

The Chinese version of the FAST has satisfactory psychometric properties in terms of validity and reliability in Chinese adults with BD.