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

The World Health Organization Short Disability Assessment Schedule (DAS-s) is used for patients with schizophrenia, although no validation is available. This manuscript addresses this issue by dealing with its psychometric properties in a clinical sample of patients with schizophrenia.

Two hundred forty-one patients from 10 Adult Mental Health Care Centers meeting the following inclusion criteria were included: (1) International Classification of Diseases, 10th Revision, diagnosis of schizophrenia; (2) Global Assessment of Functioning scores 50 or less; (3) illness duration of more than 2 years; and (4) clinical stability at assessment time. Patients were evaluated at baseline and at 1-year follow-up regarding disability, sociodemographic and clinical variables, psychosocial measures, and use of mental health services.

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 1-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 1-year follow-up, there was a nonsignificant decrease in DAS-s scores; and patients improved significantly in overall functioning and psychiatric symptoms.

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.