Insomnia Severity Index: algunos indicadores acerca de su fiabilidad y validez en una muestra de personas mayores

The Insomnia Severity Index (ISI) is a short instrument developed to assess insomnia severity from which there is no study in Spain that guarantees its psychometric properties.To examine the reliability, factorial structure, and convergent and discriminant validity of the Spanish version of the ISI in an older adult sample.A sample of 230 older adults, aging from 56 to 87 years old (71,11 +/- 5,56) filled in the ISI, together with Athens Insomnia Scale-5 (AIS-5) and Mini Mental State Examination (MMSE).Principal component analysis shows only one factor which explains 68.99% of total variance, with an internal consistency reliability equals 0.91. Regarding its validity, ISI shows statistically significant positive correlations with AIS-5 (r = 0.93) and negative with MMSE (r = -0.15). Moreover, it differentiates between men and women, people with and without cognitive impairment, and people with and without medical treatment.First data of the Spanish version of the ISI endorse single-dimensional structure, with an appropriate internal consistency reliability, and evidences of its measures validity.