Content area
Full Text
We explored the factor structure and psychometric properties of the Insomnia Severity Index (ISI) using 3 samples totaling 2,066 Mainland Chinese undergraduates. All participants completed the ISI and Sample 2 completed 3 other related measures. Their responses were processed using exploratory factor analysis (EFA), confirmatory factor analysis (CFA), and multiple group analyses. The EFA results revealed a 2-factor structure, whereas the CFA results supported a 3-factor solution, the latter of which was further confirmed by the results of multiple group analyses. The Chinese version of the ISI had a satisfactory Cronbach's alpha coefficient of internal reliability, 2-week test-retest reliability, and criterion validity. Overall, we found that the ISI is a reliable, valid, and psychometrically sound measure of insomnia for use with Mainland Chinese undergraduates.
Keywords: insomnia, Insomnia Severity Index, factor structure, psychometric properties, Mainland Chinese undergraduates.
Insomnia, defined as the inability to obtain sufficient sleep-especially when chronic-difficulty in falling or staying asleep, or sleeplessness, is a prevalent physical and mental health problem (Morin, LeBlanc, Daley, Gregoire, & Mérette, 2006) that has been linked to a significant burden in terms of functional impairment (Ustinov et al., 2010). The prevalence of insomnia in Mainland Chinese undergraduates, who are experiencing increasingly high levels of academic and employment stress, is reported as ranging from 19.4% to 53.3% (Hu, 2003; J. Liu, Lu, & Zhang, 2012). Insomnia significantly undermines academic performance (Curcio, Ferrara, & De Gennaro, 2006) and increases the risk of various mental health problems, such as depression and anxiety (Eller, Aluoja, Vasar, & Veldi, 2006; Roane & Taylor, 2008). Thus, to assess the severity of insomnia in Chinese undergraduates, a brief and efficient self-report questionnaire is required.
Currently, questionnaires developed by individual researchers for use in a single study and the Chinese version (X. C. Liu et al., 1996) of the Pittsburgh Sleep Quality Index (PSQI; Buysse, Reynolds, Monk, Berman, & Kupfer, 1989), are the primary methods used to assess undergraduates' insomnia in a Chinese context. However, the former are principally utilized by their respective developers and seldom by others owing to poor validity and reliability, and although the PSQI provides a subjective estimate of general sleep quality or disturbance, it is not specifically targeted at assessing the degree of impairment or emotional distress associated with insomnia.