Sleep hygiene can be described as practices to ease sleep and to avoid factors which decrease sleep quality. Inadequate sleep hygiene generally results in disturbance of daily life activities due to inability to sustain sleep quality and daytime wakefulness. The aim of the study was to assess psychometric properties of the Sleep Hygiene Index in clinical and non-clinical Turkish samples.

Data were collected from 106 patients with major depression and 200 were volunteers recruited from community sample who were enrolled at the university. The Sleep Hygiene Index (SHI), Pittsburgh Sleep Quality Index (PSQI), Insomnia Severity Index (ISI) and Epworth Sleepiness Scale (ESS) were administered to the subjects. All depression patients and thirty-two healthy volunteers underwent a twenty-day test-retest procedure. Factor structure of the SHI was evaluated with explanatory and multi-sample confirmatory factor analyses. Pearson product-moment correlation coefficients of the SHI with the PSQI, ISI and ESS were performed. Item analyses, internal consistency coefficients and intra-class correlations between two repeated applications in both patient and healthy subjects were calculated.

Cronbach's alphas for the SHI in community sample and patients with major depression were 0.70 and 0.71, respectively. Scale scores had comparatively good temporal stability over a three-week time for either clinical or non-clinical samples. SHI had good internal reliability.

The findings of this present study suggest that the SHI may be a useful research or clinical assessment tool for evaluating sleep hygiene to guide case formulation, treatment planning in depression as well as nonclinical population.