Center for Research in Neuropsychology and Cognitive Behavioral Intervention

The Pittsburgh Sleep Quality Index (PSQI) is a self-response questionnaire developed by Buysse et al. (1989), originally to discriminate between “good” and “poor” adult sleepers. Both for clinical and non-clinical applications, it may help to identify the main areas in which sleep may (or may not) be disturbed.

 

The PSQI has been translated into several languages, and there is more than one Portuguese version. The one mentioned here is the MAPI Institute “Portuguese for Portugal” translation indicated by the University of Pittsburgh, which was validated to Portugal by Gomes et al. (2018) including reliability, validity, norming (M +/- SD by age group, sex, and clinical vs. non-clinical group), and clinical accuracy (i.e., sensitivity and specificity) studies.

 

The PSQI consists of 19 items (plus 5 clinically relevant questions not considered for scoring purposes), which are distributed into seven “components”: subjective sleep quality; sleep latency; sleep duration; habitual sleep efficiency; sleep disturbances; use of sleeping medication; day-time dysfunction. Each component is scored from 0 a 2, and the sum of the component scores yields a global PSQI score.

According to Buysse et al. (1989), an overall score of 6 points or higher may be used to identify poor sleepers. The Portuguese validation study of Gomes et al. (2018) has confirmed this cut-off point was suitable for the European Portuguese version too and, in addition, has found an optimal cut-off point to discriminate between non-clinical and clinical sleep patients of 8 points or higher.