Psychometric properties and validation of the Spanish versions of the overall anxiety and depression severity and impairment scales

Background: Anxiety and depressive disorders are the most frequent disorders for which patients seek care in public health settings in Spain. This study aimed at validating the Overall Anxiety Severity and Impairment Scale (OASIS) and the Overall Depression Severity and Impairment Scale (ODSIS), which are brief screening scales for anxiety and depression consisting of only five items each. Methods: The study was conducted in a Spanish clinical sample receiving outpatient mental health treatment (N = 339). A subsample of participants (n = 219) was assessed before and after receiving a course of cognitive-behavioral treatment. Results: The results revealed excellent internal consistency estimates (Cronbach's alpha for the OASIS and the ODSIS was 0.87 and 0.94, respectively), along with promising convergent and discriminant validity and test-criterion relationships (i.e., moderate correlation with other measures of depression and anxiety, as well as with neuroticism, quality of life, adjustment, and negative affect). A one-dimensional structure was obtained for the OASIS and the ODSIS. The ROC analyses indicated an area under the curve of 0.83 for the OASIS and the ODSIS when predicting moderate-to-severe anxiety and depression, respectively. Good sensitivity to therapeutic change was also evidence and the analysis of the sensitivity as a function of 1-specificity area suggested a cutoff value of 10 for both scales. Limitations: Inter-rater reliability of diagnoses with the ADIS-IV interview could not be investigated and the results obtained may not be generalizable to other samples and health settings. Conclusions: The availability of these two short and psychometrically sound measures should make screening of anxiety and depressive symptoms in routine care more feasible.