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.