Correspondence: Zai-Ting Yeh, Department of Clinical Psychology, Fu Jen Catholic University, 510 Chung Cheng Road, Hsinchuang, Taipei 24205, Taiwan. Tel: + 886 2 29053487. Fax: + 886 2 87322818. E-mail: yehzaiting@ntu.edu.tw (Received: 26 April 2011; accepted 8 November 2011) ORIGINAL ARTICLE Development of the Insomnia Screening Scale Based on ICSD-II ZAI-TING YEH 1 , RAYLEIGH PING-YING CHIANG 2,3 , SHIH-CHUNG KANG 4 & CHIA-HSUAN CHIANG 1 1 Department of Clinical Psychology, Fu Jen Catholic University, Taipei, Taiwan, 2 School of Medicine, Fu Jen Catholic University, Taipei, Taiwan, 3 Shin Kong WHS Memorial Hospital, Taipei, Taiwan, and 4 Department of Civil Engineering, National Taiwan University, Taipei, Taiwan Abstract 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 estab- lish 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 symp- toms but also examines the sleep environment and sleep opportunities of the participants. Key Words: Insomnia, ICSD-II, reliability , validity , working memory Introduction Insomnia is a sleep disturbance that affects many people’ s daily function and reflects some of psycho- logical problem or physiological disorders. Its preva- lence on a regular basis is 9% for persistent sleep disturbances in the United States [1], 9.2% in Main- land China [2] and 25% for occasional insomnia in Taiwan [3]. Prevalence is especially high in elderly adults, with 32.9% in China [4] and up to 36.7% in the United States [5,6]. Since insomnia is a common index of health problems [7], some studies have indi- cated that insomnia is a predictor of psychiatric dis- orders such as depression and anxiety [8,9].Therefore, developing a scale for screening for insomnia in the community is an important issue for future diagnos- tic use, general health care, and academic research. The most widely used diagnosis system for insom- nia is the International Classification of Sleep Disor- ders (ICSD) [10,11]. According to the revised second edition, insomnia is defined as a persistent sleep dif- ficulty and associated daytime impairment, excluding an inappropriate sleep environment and opportunity [12]. Therefore, based on the diagnostic criteria of the ICSD-II, the main concepts are sleep difficulty, day- time function, sleep environment, and sleep oppor- tunity. Sleep difficulty includes not only difficulty with initiation, sleep disruption, and insufficient sleep but also poor quality and non-restorative sleep. Daytime impairment may include fatigue, poor atten- tion, memory impairment, and mood disturbances. Some specific types of workers are prone to a lack of adequate sleep opportunities, such as 24-h shift workers, nursing staff, and scientific researchers. An inadequate sleep environment may include noise, humidity, air conditioning, and bright light in the bedroom. For most of these individuals, if a good sleep opportunity and environment are provided, insomnia symptoms will disappear. International Journal of Psychiatry in Clinical Practice, 2012; 16: 259–267 ISSN 1365-1501 print/ISSN 1471-1788 online © 2012 Informa Healthcare DOI: 10.3109/13651501.2011.640938 Int J Psych Clin Pract Downloaded from informahealthcare.com by National Taiwan University on 02/26/15 For personal use only.