The Dysfunctional Beliefs and Attitudes about Sleep scale: Dimensions of the European Portuguese DBAS-30 and development of a new short version (DBAS-SF-16).

OBJECTIVES: The Dysfunctional Beliefs and Attitudes about Sleep Scale (DBAS) is the most widely validated instrument for assessing sleep-related cognitions. This study aimed to examine the reliability of the DBAS-30 European Portuguese version, explore its dimensionality, and develop a new short version suitable for differentiating the presence/absence of insomnia. METHODS: From 824 participants aged 18-85 years, the Insomnia Group (IG, n = 355, 261 females and 94 males) and Normal Sleepers Group (NSG, n = 292, 237 females, 54 males and 1 with no response) were constituted. Thirty-one patients with Obstructive Sleep Apnea Syndrome were also recruited. For the DBAS 16-items version, the ability to differentiate dysfunctional beliefs between people with and without insomnia was used as the main criterion for item retention. RESULTS: DBAS-30 PT demonstrated good internal consistency and significantly discriminated IG from NSG. Based on a robust EFA (RDWLS), a three-dimensional structure was determined for IG (Ageing and Hopelessness, Sleep Expectations, and Consequences and Helplessness). DBAS-SF-16 presented as an internally-consistent measure with a reliable two-factor structure (Consequences and Helplessness, Medication and Hopelessness) and showed construct and known groups validity. ROC analysis demonstrated DBAS-SF-16's relevant clinical accuracy, and 4.3 provides the best cut-off score in detecting the level of dysfunctional beliefs associated with clinical insomnia. CONCLUSIONS: A new and meaningful dimensionality of the DBAS-30 was found. DBAS-SF-16 showed to be a reliable, valid, and robust tool for evaluating dysfunctional beliefs about insomnia in clinical and non-clinical populations.

The European Portuguese version of the insomnia severity index.

Insomnia is the most prevalent sleep complaint, but remains largely an unidentified public health issue. The Insomnia Severity Index (ISI) is a brief self-report questionnaire to assess insomnia, long-established both in clinical and research settings. The present study aimed to analyse the reliability, validity, and accuracy of the ISI European Portuguese version. After the translation protocol, 1,274 participants (65.54% female), with a mean (SD, range) age of 37.52 (16.82, 18-95) years, completed the ISI. This sample included 250 patients with insomnia from a Sleep Medicine Centre, presenting a diagnosis of insomnia disorder (Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition; International Classification of Sleep Disorders, Third Edition), and 1,024 individuals from the community. A group of 30 patients with obstructive sleep apnea (OSA) was also recruited. Cronbach's α was 0.88 (internal consistency), and corrected item-total correlations ranged from 0.56 to 0.83. An exploratory factor analysis (oblique rotation) revealed a two-factor solution for both clinical and community samples. The ISI total score significantly differentiated insomnia disorder, no insomnia, and OSA subgroups with a large effect size (η 2  = 0.42). The correlation between ISI and Pittsburgh Sleep Quality Index supported concurrent validity (0.82), and discriminant validity was confirmed by a moderate correlation between ISI and Beck Depression Inventory Second Edition (0.32). The area under the curve was 0.88, and the optimal cut-off to detect clinical insomnia was 14 (82.1% sensitivity, 79.5% specificity). In conclusion, the Portuguese version of the ISI is a reliable and valid measure of insomnia in clinical and non-clinical populations. Our present study also contributes to relevant data for the international literature regarding the cut-off score of the scale for the detection of clinical insomnia.

BaSIQS - basic scale on insomnia complaints and quality of sleep: reliability, norms, validity, and accuracy studies, based on clinical and community samples.

This research focused on the Basic Scale on Insomnia Symptoms and Quality of Sleep (BaSIQS), formerly validated in undergraduates using the Pittsburgh Sleep Quality Index (PSQI), and aimed to expand internal consistency analysis, examine thoroughly its validity, and determine its clinical accuracy. Considering objective and subjective measures, recruiting non-clinical and clinical samples, this research implemented a comprehensive approach to examine convergent and discriminant validity, confirmatory factor analyses, and the BaSIQS sensitivity and specificity. The BaSIQS was filled out along with the Insomnia Severity Index (ISI), questions on sleep-wake schedules, Composite Scale of Morningness (CSM) and Brief Symptom Inventory-18 (BSI-18) by 1198 adults, 18-64 years old, plus another 30 who wore actimeters, recruited in community settings. A clinical group of 30 chronic insomnia disorder patients also participated. Cronbach alpha coefficient was 0.80. A two-factor structure was confirmed. The association between BaSIQS and ISI was large, whereas actigraphy correlations were medium or small. Medium to non-significant correlations were found concerning conceptually different self-report measures. Comparing the clinic and control groups, the former showed poorer sleep, with a large effect size. Receiver operating characteristic analysis revealed an area under curve = 0.9, and an optimal cut-off score >15. In conclusion, results on reliability, validity, and accuracy provide support to the utility of the BaSIQS both in community and clinical settings, for research and practical purposes.