Sleep Hygiene Index: Psychometric Characteristics and Usefulness as a Screening Tool in a Sample of Nigerian Undergraduate Students.

STUDY OBJECTIVES: The objectives of this study were to investigate the psychometric properties of the Sleep Hygiene Index (SHI) and determine its capacity to screen for poor sleep quality in a nonclinical sample of Nigerian university students. METHODS: A total of 348 students appropriately completed the SHI, the Morningness-Eveningness Questionnaire (MEQ), the Pittsburgh Sleep Quality Index (PSQI), and the Epworth Sleepiness Scale (ESS). RESULTS: The internal consistency (Cronbach alpha) of the SHI was .64 and its construct validity was modestly satisfactory. It had a significant negative correlation with the MEQ (r = -.170, P < .001) and positive correlations with global PSQI (r = .289, P < .001) and ESS (r = .219, P < .001) scores. Prior to the factor analysis, our sample was randomly divided into two. In one half of the sample (sample 1), exploratory factor analysis of the SHI items yielded a three-factor model. Confirmatory factor analysis on the other half (sample 2) corroborated this model with satisfactory indices of fitness (c2 = 67.805; df = 55; c2/df = 1.233; P = .115; goodness of fit index = .943; Tucker-Lewis index = .958; incremental fit index = .972; comparative fit index = .970; root mean square error of approximation = .037). A cutoff total score of 16 on the SHI had the best sensitivity (77.0%) and specificity (47.5%) to identify students who were categorized as experiencing poor sleep quality, according to the PSQI (area under the curve = 0.65, 95% confidence interval = 0.59-0.71). CONCLUSIONS: The SHI exhibited satisfactory psychometric properties as a self-rated assessment instrument in the evaluation of sleep hygiene and as a screening instrument for poor sleep quality among Nigerian undergraduate students.