The Pittsburgh Sleep Quality Index: a brief review

The Pittsburgh Sleep Quality Index (PSQI) was first developed in 1989 by David J. Buysse and colleagues to assess sleep quality, particularly in clinical populations, with a focus on individuals with psychiatric disorders [1]. At the time, the authors noted that, despite the high frequency of sleep complaints associated with such conditions, there was a lack of standardized instruments to measure sleep quality and disturbances. Since its introduction, the PSQI has become widely adopted in both research and clinical settings, within and outside the fields of psychiatry and sleep medicine [2]. Being largely employed in diverse clinical samples, as well as in the general population and epidemiological studies, the questionnaire is now unanimously recognized as the most common subjective measure of sleep quality. As of October 2024, the original 1989 study has been cited 37 666 times on Google Scholar and 23 78 times on Scopus, and the PSQI is frequently mentioned as a key tool for clinical assessment in leading sleep medicine textbooks [3,4].