Assessing circadian preferences in Portuguese adolescents: development and preliminary validation of a reduced Morningness–Eveningness Questionnaire

Our work aimed to provide a validated reduced form of the Morningness–Eveningness Questionnaire to Portuguese adolescents (ages: 12–14 years). Using the dataset from the initial validation study of the full questionnaire (19 items) to Portuguese adolescents, we derived a 10-item reduced form – aMEQ-R (Phase 1); this was the smallest set of items that allowed us to obtain acceptable internal consistency. This reduced version was then submitted to an independent validation study (Phase 2). Participants in this phase responded to our reduced 10-item version and, 3–4 weeks later, the same participants responded to the full Morningness–Eveningness Questionnaire. In both sessions we also assessed trait-anxiety, a variable that has been related to chronotype in order to obtain an additional measure of validation. Acceptable internal consistency was obtained in this dataset, such as Cronbach’s alpha = .717, as well as other indexes (e.g. classification agreement). Moreover, we confirmed that the aMEQ-R is sensitive to capture the usually reported relation between an eveningness tendency and higher trait-anxiety. In this preliminary study, we propose a suitable reduced instrument to assess chronotype in Portuguese adolescents.

Abbreviations: aMEQ-R: Reduced form of the Morningness-Eveningness Questionnaire for Adolescents; aMEQ: Morningness-Eveningness Questionnaire for Adolescents; MEQ: Morningness-Eveningness Questionnaire; CSM: Composite Scale of Morningness; TASC: Trait Anxiety Scale for Children; SM: Supplemental Material.