Validation of a 3-factor scoring model for the Pittsburgh sleep quality index in older adults.

STUDY OBJECTIVES

The Pittsburgh Sleep Quality Index (PSQI) is widely used to assess subjective sleep disturbances in psychiatric, medical, and healthy adult and older adult populations. Yet, validation of the PSQI single-factor scoring has not been carried out.

DESIGN

The PSQI was administered as a self-report questionnaire. Using a cross-validation approach, scores from the PSQI were analyzed with exploratory and confirmatory factor analyses.

SETTING

San Diego, Denver, and Los Angeles community-based clinics.

PARTICIPANTS

Community-dwelling depressed and nondepressed adults older that 60 years of age (N = 417)

MEASUREMENTS AND RESULTS

Results yielded a 3-factor scoring model that obtained a measure of perfect fit and was significantly better fitted than either the original single-factor model or a 2-factor model. Components of the 3 factors were characterized by the descriptors sleep efficiency, perceived sleep quality, and daily disturbances.

CONCLUSIONS

These findings validate the factor structure of the PSQI and demonstrate that a 3-factor score should be used to assess disturbances in three separate factors of subjective sleep reports.