The World Health Organization Short Disability Assessment Schedule: a validation study in patiens with schizophrenia

Abstract

Purpose: The World Health Organization Short Disability Assessment Schedule (DAS-s) is used for patients with schizophrenia even though no validation is available. This paper addresses this issue by dealing with its psychometric properties in a clinical sample of patients with schizophrenia. Methods: Two hundred forty-one patients from 10 Adult Mental Health Care Centres (AMHCC) meeting the following inclusion criteria were included: 1) International Classification of Diseases-10 or ICD-10 diagnosis o schizophrenia; 2) Global Assessment of Functioning scores or GAF ≤50; 3) Illness duration of more than 2 years; and 4) Clinical stability at assessment time. Patients were evaluated at baseline and at one-year follow-up regarding disability, socio-demographic and clinical variables, psychosocial measures and use of mental health services. Results: The factor analysis revealed a single factor that explained 60.57% of the variance. Internal consistency values were appropriate for the DAS-s total (0.78 at baseline and 0.78 at one year follow-up). Correlations between DAS-s scores and those of global functioning, psychiatric symptoms, social support and quality of life ranged between small and moderate (range: 0.13-0.39). There were significant differences between groups of patients with schizophrenia in the DAS-s. Patients who were unemployed, with lower global functioning, with cognitive impairment and lacking social support scored significantly lower in DAS-s scores. After one year follow-up, there was a non-significant decrease in DAS-s scores and patients improved significantly in overall functioning and psychiatric symptoms. Discussion: This study shows that the DAS-s has good reliability and validity, and suggests that it is suitable for the assessment of disability in patients with schizophrenia.