Thirty-five years of the Pittsburgh sleep quality index: a critical appraisal and a path forward for its contemporary...

Since its publication in 1989, the Pittsburgh sleep quality index (PSQI) has become one of the most widely used self-report instruments in sleep medicine. Despite its enduring popularity, its extensive adoption has been accompanied by conceptual and methodological concerns regarding its psychometric foundations and the construct it purports to measure. This review offers a critical appraisal of the PSQI nearly four decades after its introduction and outlines directions for its contemporary use. Five interrelated issues are examined: (i) the absence of a clearly specified construct model of "sleep quality"; (ii) the frequent use of the PSQI as a proxy for insomnia or sleep disturbance; (iii) the interpretive fragility of the conventional global score cutoff (>5); (iv) heterogeneity in component scoring logic and instability of factorial structure; and (v) the redundancy and recall vulnerability of retrospective sleep continuity estimates. Drawing on the shift from "sleep quality" toward multidimensional sleep health, we propose reframing PSQI outputs within a theoretically grounded sleep health perspective. Accordingly, alternative strategies for scoring, reporting, and interpretation are discussed to preserve the value of this legacy instrument while improving its conceptual alignment with contemporary models of sleep assessment.