TNF and insomnia: The aims of this study were: (1) to analyze insomnia in a population of university students and the association between sleep quality and several factors such as depressive symptoms and self-perceived stress, drinking beverages containing caffeine, smoking, and alcohol intake; (2) to evaluate whether the concentration of salivary inflammatory markers IL-1β, IL-6, and TNFα is associated with insomnia and the discrimination accuracy of these cytokines to classify individuals with or without insomnia.