Pittsburgh Sleep Quality Index (PSQI) [27]

The PSQI is a 19-item measure which assesses past-month sleep quality and produces seven component scores ranging from 0 to 3, with higher scores corresponding to poorer sleep quality. Components include subjective sleep quality, sleep onset latency, sleep duration, sleep efficiency [(% of time spent sleeping / time spent in bed) × 100], sleep disturbances, sleep medication use, and daytime dysfunction. Component scores are totaled to produce a global score ranging from 0 to 21, with scores above 5 indicative of poor sleep quality [27]. Cronbach’s alpha for PSQI in the current sample was 0.72.