Anxiety symptomatology, sex and chronotype: The mediational effect of diurnal sleepiness.

Diurnal subjective sleepiness has been associated with a large number of negative outcomes, such as increased risk of accidents and development of mental disorders as depression and anxiety. However, the role of the diurnal subjective sleepiness as a mediator is poorly understood. The goal of the present study was to examine the role of diurnal subjective sleepiness as a mediator of the relationship between sex, chronotype and anxiety symptoms in healthy young adults. Four-hundred and sixty-seven healthy young adults (64.8% females, age range 18-32 years, mean 20.7, ±2.3) were evaluated with validated and widely used scales for the measurement of diurnal sleepiness, anxiety symptoms and morningness-eveningness preference. We have found that diurnal subjective sleepiness correlated with anxiety symptoms when evaluated both in the total sample and within chronotypes. This association was more important in females than in males (p < 0.0001). Regarding chronotype, only for morning-types, diurnal subjective sleepiness was a significant mediator of the relationship between sex and anxiety symptoms. This is the first study that examines the mediator role of diurnal subjective sleepiness in the known relationship between sex and anxiety symptoms, and adds new evidence about the effect of the chronotype on sleep problems and mental health. Although future work is required, our results have important implications for clinical settings and public health interventions.