title: Dimensionality of the Pittsburgh Sleep Quality Index in the collegiate young adults.
abstract: OBJECTIVE
  To explore and validate the factor structure of the Pittsburgh Sleep Quality Index (PSQI) in the collegiate young adults.
  
  
  METHODS
  Six hundred university students were initially contacted and invited to participate in a survey of their sleep experience and history. Of this preliminary sample 418 of the students (age = 20.92 ± 1.81 years, BMI = 23.30 ± 2.57 kg/m(2)) fulfilled the screening criteria and ultimately completed the Pittsburgh Sleep Quality Index (PSQI), a self-report survey of respondents' sleep habits and sleep quality. The students were enrolled in various undergraduate and postgraduate programs at Jamia Millia Islamia, New Delhi, India. Exploratory factor analysis (EFA) investigated the latent factor structure of the scale. Confirmatory factor analysis evaluated both of the models found by EFA.
  
  
  RESULTS
  The Kaiser's criteria, the Scree test, and the cumulative variance rule revealed that a 2-factor model accounted for most of the variability in the data. However, a follow up Parallel Analysis found a 1-factor model. The high correlation coefficient (r = 0.91) between the two factors of the 2-factor model and almost similar values of the fit indices supports the inference that the PSQI is a unidimensional scale.
  
  
  CONCLUSIONS
  The findings validate the 1-factor model of the PSQI in the collegiate young adults.
authors.affiliation: Department of Biomedical Sciences, College of Health Sciences, Mizan Tepi University (Mizan Campus), Mizan Aman Town, Ethiopia ; Centre for Physiotherapy and Rehabilitation Sciences, Jamia Millia Islamia, New Delhi, India.
authors.forename: Md Dilshad
authors.initials: MD
authors.lastname: Manzar
authors.affiliation: Centre for Physiotherapy and Rehabilitation Sciences, Jamia Millia Islamia, New Delhi, India.
authors.forename: Wassilatul
authors.initials: W
authors.lastname: Zannat
authors.affiliation: Centre for Physiotherapy and Rehabilitation Sciences, Jamia Millia Islamia, New Delhi, India.
authors.forename: M Ejaz
authors.initials: ME
authors.lastname: Hussain
authors.affiliation: Somnogen Canada Inc, College Street, Toronto, ON Canada.
authors.forename: Seithikurippu R
authors.initials: SR
authors.lastname: Pandi-Perumal
authors.affiliation: The University Sleep Disorders Center, Department of Medicine, College of Medicine, and National Plan for Science and Technology, College of Medicine, King Saud University, Riyadh, Saudi Arabia.
authors.forename: Ahmed S
authors.identifier: 0000-0002-1706-6167
authors.initials: AS
authors.lastname: Bahammam
authors.affiliation: Department of Psychiatry, Faculty of Medicine, Ain Shams University, Cairo, Egypt.
authors.forename: Doaa
authors.initials: D
authors.lastname: Barakat
authors.affiliation: Center for Healthful Behavior Change, Department of Population Health, New York University Medical Center, New York, NY USA.
authors.forename: Nwakile Izuchukwu
authors.initials: NI
authors.lastname: Ojike
authors.affiliation: The University Sleep Disorders Center, Department of Medicine, College of Medicine, and National Plan for Science and Technology, College of Medicine, King Saud University, Riyadh, Saudi Arabia.
authors.forename: Awad
authors.initials: A
authors.lastname: Olaish
authors.affiliation: 323 Brock Ave., Toronto, ON M6K 2M6 Canada.
authors.forename: D Warren
authors.initials: DW
authors.lastname: Spence
keywords: Collegiate, young adults; Confirmatory factor analysis; Exploratory factor analysis; Model fit; Students