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

To describe and validate the Athens Insomnia Scale (AIS).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.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.The high measures of consistency, reliability, and validity of the AIS make it an invaluable tool in sleep research and clinical practice.