Document Type : Original Article


1 Department of Educational Sciences, Malayer University, Malayer, Iran, 2 M.A. in Mind, Brain and Education Science, Independent Researcher, Tehran, Iran

2 M.A. in Mind, Brain and Education Science, Independent Researcher, Tehran, Iran

3 Ph.D. in Higher Education Management, Independent Researcher, Tehran, Iran

4 Deparment of Psychiatry, Universidade Federal de São Paulo, São Paulo, SP, Brazil

5 Deparment of Psychiatry, Universidade Federal de São Paulo, São Paulo, SP, Brazil, 5 School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam School of Public Health, University of Hong Kong, Hong Kong, China

6 Deparment of Psychobiology, Universidade Federal de São Paulo, São Paulo, SP, Brazi


BACKGROUND: The Pediatric Daytime Sleepiness Scale (PDSS) and the Morningness–Eveningness
Scale for Children (MESC) are widely used to measure two important facets of sleep patterns, but
neither have been adapted and validated for use in Iran. The purpose of this study was to examine
the psychometric properties and factor structure of the Persian versions of the PDSS and the MESC
in a sample of Iranian adolescents.
MATERIALS AND METHODS: The Persian versions of PDSS and MESC were translated and
administered to a representative sample (n = 407) of Iranian early adolescents, aged 9–15 years,
who attended school in morning shifts. The factor structure of both scales, found in prior studies,
was tested using Confirmatory Factor Analyses to assess their validity and reliability.
RESULTS: The results revealed that the model fit indices of the one factor solution of the PDSS
and the two factor solution of the MESC were acceptable to good. A high Pearson correlation was
found between raw and latent factor scores for the PDSS and the two factors derived from the
MESC (i.e., Morningness and Planning). Furthermore, the higher the PDSS score (more daytime
sleepiness), the lower the MESC scores (more eveningness), indicating criterion validity of the scales
showing the expected increase in daytime sleepiness in evening oriented adolescents who wake
up early for attending school.
CONCLUSION: The Persian versions of the PDSS and the MESC can be considered reliable and
valid tools for evaluating, respectively, daytime sleepiness and morningness‑eveningness in the
adolescent population of Iran.


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