The self-morningness/eveningness (Self-ME): An extremely concise and totally subjective assessment of diurnal preference

The assessment of diurnal preference, or the preferred timing of sleep and activity, is generally based on comprehensive questionnaires such as the Horne–Ostberg (HO). The aim of the present study was to assess the reliability of a subject’s self-classification as extremely morning (Self-MM), more morning than evening (Self-M), more evening than morning (Self-E) or extremely evening (Self-EE) type, based on the last question of the HO (Self-ME). A convenience sample of 461 subjects [23.8 ± 4.7 years; 322 females] completed a full sleep–wake assessment, including diurnal preference (HO), night sleep quality (Pittsburgh Sleep Quality Index, PSQI), daytime sleepiness (Karolinska Sleepiness Scale, KSS), and habitual sleep–wake timing (12 d sleep diaries; n = 296). Significant differences in HO total score were observed between Self-ME classes, with each class being significantly different from neighboring classes (p < 0.0001). Significant differences in sleep–wake timing (bed time, try to sleep and sleep onse...