Validity and reliability of the Finnish version of the Functioning Assessment Short Test (FAST) in bipolar disorder

The Functioning Assessment Short Test (FAST) was developed for the clinical evaluation of functional impairment of patients suffering from bipolar disorder. The aim of this study was to validate the Finnish version of FAST.

Translation and back-translation of FAST were performed. Fifty patients with the Diagnostic and Statistical Manual of Mental Disorders-Fourth edition (DSM-IV) bipolar type I and II were interviewed at the Bipolar Disorder Research and Treatment Centre, City of Helsinki, Finland. Participants completed the FAST, the Social and Occupational Functioning Assessment Scale (SOFAS) of DSM-IV, and the Sheehan Disability Scale (SDS) as part of the assessment. Internal consistency and correlations between FAST and SOFAS and SDS were analysed. Twenty-five patients participated in a reliability assessment carried out 1 week apart by a different rater.

The internal consistency coefficient obtained was very good, with a Cronbach alpha of 0.870. Reliability of FAST was also found excellent (correlation between two measures r = 0.896, p < 0.001). A highly significant negative correlation between FAST and SOFAS scores was found (r = -0.723, p < 0.001). FAST and SDS were also highly significantly correlated (r = 0.742, p < 0.001).

The psychometric validity and reliability of FAST in the Finnish sample of patients with bipolar disorder types I and II were good.