Concurrent Validity and Reliability of the Brazilian Version of the Functioning Assessment Short Test in Patients with Schizophrenia

OBJECTIVE: Many studies have documented the high rates of functional impairment among patients with schizophrenia. The majority of the available instruments used to assess functioning, however, focus on global measures of functional recovery rather than specific domains of psychosocial functioning. Most of these instruments have important limitations regarding use in psychiatry. The aim of the present study was to evaluate the psychometric properties of the Brazilian version of the Functioning Assessment Short Test (FAST) in patients with schizophrenia. METHODS: A convenience sample of 107 chronic outpatients with schizophrenia and 108 controls was assessed in a university hospital (Hospital de Clínicas de Porto Alegre, Brazil). Psychometric properties of FAST (internal consistency, concurrent validity, and test-retest reliability) were analyzed. RESULTS: The internal consistency obtained was high; the Cronbach's alpha was 0.89. FAST total score was higher in patients than in the control group (Z = 11.95; P<0.001). FAST test-retest agreement was excellent (intraclass correlation coefficient = 0.93; 95% confidence interval 0.81-0.97). In addition, FAST displayed a positive correlation with the Brief Psychiatric Rating Scale (ρ = 0.41; P<0.001) and a negative correlation with the Global Assessment of Functioning scale (ρ =-0.71; P = 0.001). CONCLUSIONS: Psychotic symptoms, comorbidity, and functional and cognitive impairment contribute to the decreased quality of life of patients with schizophrenia. It is important to obtain a valid and reliable instrument that is capable of evaluating the functional domains in this pathology. In this context, FAST showed accurate psychometrics properties and was able to detect functional differences between patients with the diagnosis of schizophrenia and healthy subjects.