The Sleepiness–Depression Link in Obstructive Sleep Apnea: Preliminary Results on the Mediation of Impulsivity

Background: Emotional impulsivity has been found to be relevant in explaining the association between sleep problems and depressive symptoms, suggesting the potential role of impulsivity as a key underlying mechanism of this link. The objective of this study was to take a preliminary step in understanding the mediating role of impulsivity in the relation between excessive daytime sleepiness (EDS) and depression in patients with obstructive sleep apnea syndrome (OSAS) and to compare psychological and demographic characteristics between different levels of daytime sleepiness. Methods: A total of 138 patients with OSAS underwent polygraphic cardiorespiratory monitoring and completed a series of questionnaires investigating perceived sleepiness, depression, impulsivity, and other psychological characteristics. A mediational model was tested in order to assess whether impulsivity mediated the relation between sleepiness and depressive symptoms while controlling for the effects of age, sex, BMI, and oxygen saturation parameters. Results: the mediation model showed that there was a significant indirect effect of impulsivity in the sleepiness–depression link (αβ = 0.084 [0.0243–0.1617]). Conclusions: The here-presented results showed that the sleepiness–depression link is not direct as previous studies asserted, but instead it may be better explained by impulsivity. Research and practical implications are discussed.