title: Comparing three morningness scales: age and gender effects, structure and cut-off criteria.
abstract: OBJECTIVE
  To add to the validity of the French version of the Composite Scale of Morningness (CSM) by comparing its structure with that of the Morningness-Eveningness Questionnaire (MEQ), the most widely used scale to measure circadian typology. Second, to compare the cut-off criteria used to transform the continuous scores into categorical chronotypes. Third, to further test the effects of age and gender on morningness scores. The rMEQ, a shortened version of the MEQ, is also considered.
  
  
  METHODS
  Four hundred and fifty-six students served as volunteer subjects and filled the CSM and the MEQ.
  
  
  RESULTS
  There was no effect of gender, and the CSM and MEQ scores correlated above (+) 0.90 in both genders. Regarding age, morningness was stable before age 35 and increased afterwards. We replicated the three-factor structure of the CSM previously reported in five different cultures. The MEQ is longer and counted a fourth factor while the first three factors were quite identical to those extracted from the CSM. This comparative study emphasizes the recurrent problem of cut-off scores: the available values for both instruments result in a very poor concordance of chronotypes.
  
  
  CONCLUSIONS
  Belonging to the evening-type is regarded as a risk factor for sleep disorders and its positive predictive value should be correctly assessed. Hence, normative scores standardized in such a way they reflect the effects of age, gender and culture are needed for the total score and the factor scores. To this extent, T-scores (with a mean of 50 and standard deviation of 10) would be suitable, and normative tables for French subjects (N = 1598) are given as supplemental data.
authors.affiliation: Pôle Enfant-Adolescent, CHU de Nice, Hôpital Archet 2, F-06202 Nice Cedex 3, France. caci.h@chu-nice.fr
authors.forename: Hervé
authors.initials: H
authors.lastname: Caci
authors.forename: Olivier
authors.initials: O
authors.lastname: Deschaux
authors.forename: Ana
authors.initials: A
authors.lastname: Adan
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Natale
mesh_terms: D000204:Activity Cycles / Q000502:physiology*; D000293:Adolescent; D000328:Adult; D000367:Age Factors; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D012307:Risk Factors; D012649:Self Concept; D012737:Sex Factors; D012893:Sleep Wake Disorders / Q000175:diagnosis* / Q000209:etiology / Q000503:physiopathology*; D011795:Surveys and Questionnaires; D014851:Wakefulness / Q000502:physiology*; D055815:Young Adult