Athens Insomnia Scale: validation of an instrument based on ICD-10 criteria.

OBJECTIVES: To describe and validate the Athens Insomnia Scale (AIS). METHODS: The AIS is a self-assessment psychometric instrument designed for quantifying sleep difficulty based on the ICD-10 criteria. It consists of eight items: the first five pertain to sleep induction, awakenings during the night, final awakening, total sleep duration, and sleep quality; while the last three refer to well-being, functioning capacity, and sleepiness during the day. Either the entire eight-item scale (AIS-8) or the brief five-item version (AIS-5), which contains only the first five items, can be utilized. The validation of the AIS was based on its administration to 299 subjects: 105 primary insomniacs, 144 psychiatric patients and 50 non-patient controls. RESULTS: Regarding internal consistency, for both versions of the scale, the Cronbach's alpha was around 0. 90 and the mean item-total correlation coefficient was about 0.70. Moreover, in the factor analysis, the scale emerged as a sole component. The test-retest reliability correlation coefficient was found almost 0.90 at a 1-week interval. As far as external validity is concerned, the correlations of the AIS-8 and AIS-5 with the Sleep Problems Scale were 0.90 and 0.85, respectively. CONCLUSION: The high measures of consistency, reliability, and validity of the AIS make it an invaluable tool in sleep research and clinical practice.