Assessing insomnia in adolescents: comparison of Insomnia Severity Index, Athens Insomnia Scale and Sleep Quality Index.

OBJECTIVES To compare the psychometric properties of the Chinese versions of Insomnia Severity Index (ISI), Athens Insomnia Scale (AIS) and Sleep Quality Index (SQI) for assessment and screening of insomnia in adolescents. METHODS This is a school-based survey of 1516 adolescents aged 12-19 years. Sleep-wake habit questionnaire, ISI, AIS, SQI, Epworth Sleepiness Scale (ESS) and 12-item General Health Questionnaire (GHQ-12) were administered. Insomnia Interview Schedule was used to assess the severity of insomnia symptoms and DSM-IV-TR diagnosis of insomnia. RESULTS The Cronbach's alpha of ISI, AIS and SQI were 0.83, 0.81 and 0.65, respectively, and the 2-week test-retest reliability were 0.79, 0.80 and 0.72. All three scales had a 2-factor structure, and their scores were significantly correlated with sleep-wake variables, ESS and GHQ-12 scores, smoking and drinking habits, and academic performance. The areas under curve of ISI, AIS and SQI for detecting clinical insomnia were 0.85, 0.80 and 0.85, respectively. The optimal cut-offs for ISI, AIS and SQI were a total score of nine (sensitivity/specificity: 0.87/0.75), seven (sensitivity/specificity: 0.78/0.74) and five (sensitivity/specificity: 0.83/0.79), respectively. CONCLUSION The Chinese versions of ISI, AIS and SQI are reliable and valid instruments. The ISI and AIS appear to have better psychometric properties than the SQI.