Psychometric properties of Youth Self-Rating Insomnia Scale (YSIS) in Chinese adolescents

Insomnia is prevalent in adolescents. Although several insomnia scales/questionnaires are available to assess insomnia symptoms and severity for adults, no insomnia scale has been specifically developed for adolescents. This study assessed the psychometric properties of the Youth Self-Rating Insomnia Scale (YSIS) in a large sample of Chinese adolescents. The YSIS consists of 8 items assessing insomnia symptoms, perceived sleep quality and insufficiency, and impaired daytime functioning. Each item is rated on a 5-point scale. A sample of 11,626 adolescents in China completed the YSIS and a structured questionnaire to assess sleep duration, sleep problems, hypnotic use, and behavioral/emotional problems. A subsample of 242 adolescents completed retest questionnaire 2weeks later. Exploratory factor analysis (EFA), confirmatory factor analysis (CFA), and a receiver operating characteristic (ROC) curve analysis were performed. The YSIS score ranged from 8 to 40 (M=19.1, SD=6.2). Internal consistency reliability coefficient was 0.80 and 2-week test-retest reliability coefficient was 0.82. Both EFA and CFA yielded 2 dominant factors defined as insomnia symptoms (3 items) and daytime distress or impairment (5 items). The YSIS score was significantly correlated with short nocturnal sleep duration, depression, hypnotic use, sleep disordered breathing problems, restless legs syndrome, and daytime sleepiness. Similar results were obtained between male and female adolescents. The YSIS appears to be a simple, reliable and valid scale for assessing insomnia severity in adolescents. Further research is warranted to assess its psychometric properties with clinical samples and non-Chinese adolescents.