Factor structure of the Athens Insomnia Scale and its associations with demographic characteristics and depression in adolescents.

The eight-item Athens Insomnia Scale (AIS-8) is an instrument that has been used frequently to assess insomnia problems. Previous research on adults has found that the AIS-8 functioned as a sole component. This study aimed to examine the prevalence rates of insomnia problems on the AIS-8, the factor structure of the AIS-8 in adolescents and its associations with demographic characteristics and depression in adolescents. A total of 8319 adolescent students (4334 girls and 3985 boys, mean age = 14.7 years, standard deviation = 1.7 years) in southern Taiwan were recruited into this study and completed the AIS-8. We performed an exploratory factor analysis to examine the factor structure of the AIS-8, and used the parallel analysis for making decisions regarding factor retention. We also used multiple regression analysis models to determine the associations between insomnia and demographic characteristics and depression. The results found that a high proportion of adolescents had insomnia problems as measured by the AIS-8. The AIS-8 was composed of two different factors when used among a large adolescent population, including insomnia symptoms (factor 1) and subjective sleep and daytime distress (factor 2). While being male, being younger, and having depression were associated positively with the severity of insomnia symptoms (factor 1), being older, living in urban areas, and having depression were associated positively with the severity of subjective sleep and daytime distress (factor 2). Clinicians and researchers should consider the different meanings of the two factors of the AIS-8 when using this tool to assess insomnia problems in adolescents.