The Pittsburgh Sleep Quality Index (PSQI) [20]
The PSQI questionnaire was used to measure sleep quality using an 18-item scale containing seven items that included sleep quality, sleep duration, sleep latency, habitual sleep efficiency, sleep disturbance, use of sleeping medications, and daytime dysfunction [20]. Each dimension scored between 0–3, with a total score ranging from 0–21, and a higher score indicating lower sleep quality [20]. The Cronbach’s alpha for internal consistency for the use of the PSQI was 0.811.