Associations between sleep quality and domains of quality of life in a non-clinical sample: results from higher education students.

OBJECTIVE: The association between sleep quality and quality of life (QoL) in clinical samples diagnosed with sleep disorders, mental disorders, or other medical conditions has been widely investigated. However, few studies focused on this relationship in samples of mostly young and healthy adults. This study analyzed the associations between sleep quality and several dimensions of QoL in higher education students and examined whether or not sleep quality would significantly predict QoL after statistically controlling for psychopathological symptoms. DESIGN: Observational and transversal. SETTING: Non-clinical; higher education. PARTICIPANTS: A sample of 324 college students, aged 17 to 47 years (M=20.89±2.85) were enrolled. MEASUREMENTS: European Portuguese versions of the Pittsburgh Sleep Quality Index (PSQI), the WHOQOL-Bref to measure QoL, and the Brief Symptom Inventory (BSI) to measure psychopathological symptoms. RESULTS: All PSQI components were significantly associated with general QoL and the psychological and physical QoL domains. The subjective sleep quality and daytime dysfunction PSQI components were consistently associated with all WHOQOL-Bref domains and general QoL. Hierarchical regression analyses further showed that the PSQI components as a whole, and in particular subjective sleep quality, added significant contributions to the general QoL facet and to the psychological, physical, and environmental QoL domains, after controlling for psychopathological symptoms. CONCLUSIONS: Several components of sleep quality and different facets/domains of QoL are associated in higher education students, particularly subjective sleep quality, which remains a significant predictor of most aspects of QoL, regardless of the presence of psychopathological symptoms.

Basic Scale on Insomnia complaints and Quality of Sleep (BaSIQS): reliability, initial validity and normative scores in higher education students.

Based on successive samples totaling more than 5000 higher education students, we scrutinized the reliability, structure, initial validity and normative scores of a brief self-report seven-item scale to screen for the continuum of nighttime insomnia complaints/perceived sleep quality, used by our team for more than a decade, henceforth labeled the Basic Scale on Insomnia complaints and Quality of Sleep (BaSIQS). In study/sample 1 (n = 1654), the items were developed based on part of a larger survey on higher education sleep-wake patterns. The test-retest study was conducted in an independent small group (n = 33) with a 2-8 week gap. In study/sample 2 (n = 360), focused mainly on validity, the BaSIQS was completed together with the Pittsburgh Sleep Quality Index (PSQI). In study 3, a large recent sample of students from universities all over the country (n = 2995) answered the BaSIQS items, based on which normative scores were determined, and an additional question on perceived sleep problems in order to further analyze the scale's validity. Regarding reliability, Cronbach alpha coefficients were systematically higher than 0.7, and the test-retest correlation coefficient was greater than 0.8. Structure analyses revealed consistently satisfactory two-factor and single-factor solutions. Concerning validity analyses, BaSIQS scores were significantly correlated with PSQI component scores and overall score (r = 0.652 corresponding to a large association); mean scores were significantly higher in those students classifying themselves as having sleep problems (p < 0.0001, d = 0.99 corresponding to a large effect size). In conclusion, the BaSIQS is very easy to administer, and appears to be a reliable and valid scale in higher education students. It might be a convenient short tool in research and applied settings to rapidly assess sleep quality or screen for insomnia complaints, and it may be easily used in other populations with minor adaptations.