OBJECTIVE: Although various instruments have been developed to evaluate insomniac symptoms in individuals, none of them are based on the International Classification of Sleep Disorder, 2nd (ICSD-II). The purpose of this study is to develop a new scaling system, the Insomnia Screening Scale (ISS) to fit the new diagnostic criteria. METHODS: Study 1 was conducted to formulate the new items of the insomnia screening scale (ISS), which were divided into four major subscales, and establish the reliability and validity of the ISS in clinical insomniac subjects. Study 2 tested the external validity of the ISS, which was used in a community survey, and investigated the relationship between ISS and daytime function, especially working memory. RESULTS: The final version of the ISS has good internal consistency (α = 0.87-0.98), and explains 64% of the variance. The insomnia group had poor working memory performance on the cognitive tasks. CONCLUSIONS: The ICSD-II based ISS is a reliable and valid instrument for evaluating an individual's insomniac symptoms. The major difference between the ISS and the previous instruments is that the ISS not only assess the subjective insomniac and daytime symptoms but also examines the sleep environment and sleep opportunities of the participants.
OBJECTIVE: Although various instruments have been developed to evaluate insomniac symptoms in individuals, none of them are based on the International Classification of Sleep Disorder, 2nd (ICSD-II). The purpose of this study is to develop a new scaling system, the Insomnia Screening Scale (ISS) to fit the new diagnostic criteria. METHODS: Study 1 was conducted to formulate the new items of the insomnia screening scale (ISS), which were divided into four major subscales, and establish the reliability and validity of the ISS in clinical insomniac subjects. Study 2 tested the external validity of the ISS, which was used in a community survey, and investigated the relationship between ISS and daytime function, especially working memory. RESULTS: The final version of the ISS has good internal consistency (α = 0.87-0.98), and explains 64% of the variance. The insomnia group had poor working memory performance on the cognitive tasks. CONCLUSIONS: The ICSD-II based ISS is a reliable and valid instrument for evaluating an individual's insomniac symptoms. The major difference between the ISS and the previous instruments is that the ISS not only assess the subjective insomniac and daytime symptoms but also examines the sleep environment and sleep opportunities of the participants.