Validity and Reliability of the Dysfunctional Beliefs and Attitudes about Sleep Scale-10 in Iranian Clinical Population

Background: Dysfunctional cognitions and attitudes about sleep are considered as one of the most important factors underlying insomnia. Objectives: The current study aimed at investigating the validity and reliability of the dysfunctional beliefs and attitudes about sleep scale-10 (DBAS-10) in an Iranian clinical population. Methods: The clinical sample consisted of 120 patients with insomnia disorder referred to the sleep disorders clinic at Baharloo hospital in Tehran in 2015. The control group (n = 120) included a community sample volunteered to participate in the study. Sleep Diary, Pittsburgh Sleep Quality Index, Insomnia Severity Index, Pre-Sleep Arousal Scale, and Depression, Anxiety, Stress Sacle-21, were used to assess concurrent validity. Test-retest and Cronbach’ alpha were conducted to examine the reliability of the scale. Construct validity of the scale was investigated via confirmatory factor analysis. Results: The current study findings indicated that DBAS-10 had appropriate test-retest reliability (r = 0.83) and internal consistency (Cronbach’ alpha = 0.82). Total score of DBAS-10 was significantly associated with PSQI (r = 0.34), ISI (r = 0.45), the cognitive subscale of PSAS (r = 0.36), and depression (0.34), anxiety (r = 0.34) and stress (r = 0.39) subscales of DASS-21. Factor analysis indicated that the Espie et al. (2000) model had significantly better fitness in comparison with the Edinger andWohlgemuth (2001) model. The cutoff point, sensitivity, and specificity of the scale were 6.7%, 74.17% and 87.50%, respectively. Conclusions: The Persian version of DBAS-10 had proper psychometric properties for Iranian clinical population.