Psychometric assessment of the Chinese adolescent daytime sleepiness scale (CADSS)

Daytime sleepiness is common in adolescents. The daytime sleepiness scales developed for western adolescents may not be applicable to Chinese adolescents. This study assesses the psychometric properties of the Chinese adolescent daytime sleepiness scale (CADSS) in a large sample of Chinese adolescents. The CADSS consists of 7 items assessing adolescents’ general feeling of drowsiness and dozing off at different situations during daytime within the past month. Each item is rated on a 5-point scale. A sample of 11,452 adolescents in China completed the CADSS and a structured questionnaire to assess sleep duration, sleep problems, hypnotic use, and behavioral/emotional problems. A subsample of 242 adolescents completed retest questionnaire 2 weeks later. Exploratory factor analysis (EFA), confirmatory factor analysis (CFA), and a receiver operating characteristic (ROC) curve analysis were performed. The CADSS score ranged from 7 to 35 (M = 16.3, SD = 7.4). Internal consistency reliability coefficient was 0.89 and 2-week test–retest reliability coefficient was 0.77. Both EFA and CFA yielded one dominant general factor defined as daytime sleepiness, indicating that the CADSS was essentially unidimensional. The CADSS score was significantly correlated with short nocturnal sleep duration, insomnia symptoms, poor sleep quality, sleep disordered breathing problems, and hypnotic use. ROC analysis indicated that a score of 17 was an acceptable cutoff in distinguishing adolescents with poor daytime functioning. The CADSS is a simple, reliable, and valid scale for assessing daytime sleepiness in Chinese adolescents. Further research is warranted to assess its psychometric properties with clinical samples and non-Chinese adolescents.