Chapter 20 Pittsburgh Sleep Quality Index (PSQI)

20.1 Background

The Pittsburgh Sleep Quality Index (PSQI) was used to measure the quality and patterns of sleep for the participants. It asks about the quality of sleep at night over the past month. Higher scores indicate worse sleep quality - lower scores are better.

Details on the PSQI may be obtained from the University of Pittsburgh - Department of Psychiatry, along with a copy of the form and scoring instructions. The PSQI was originally published in 1989, (Buysse et al. 1989).

The PSQI yields an overall sleep quality score ranging from 0 (best sleep quality) to 21 (worst sleep quality); total scores > 5 are considered to be an indication of poor sleep quality. The total score is a sum of 7 component scores of sleep (ranging from 0-3) for:

  • duration
  • disturbance
  • latency
  • day dysfunction due to sleepiness
  • efficiency
  • overall sleep quality
  • needing meds to sleep


Buysse, Daniel J., Charles F. Reynolds, Timothy H. Monk, Susan R. Berman, and David J. Kupfer. 1989. “The Pittsburgh Sleep Quality Index: A New Instrument for Psychiatric Practice and Research.” Psychiatry Research 28 (2). Elsevier BV:193–213.