Sleep-related attentional bias in insomnia: The mediating role of arousal

Background and objectives: Characterize the nature of attentional biases toward nocturnal and diurnal sleeprelated stimuli in individuals with insomnia disorder. We investigated the contributing role of sleep -related attentional biases in insomnia severity and whether their effects on insomnia severity were mediated by arousal and valence levels of the presented stimuli. Methods: Sixty-four individuals with insomnia disorder and 70 controls completed two Posner spatial cueing tasks including both nocturnal (alarm clocks) and diurnal (fatigue) pictorial stimuli associated with neutral cues. Arousal and valence of the sleep -related stimuli were assessed using a 5 -point Likert type scale. Results: Attention biases characterized by difficulty disengaging from and increased avoidance for daytime fatigue, and by difficulty disengaging from alarm clocks were observed in individuals with insomnia disorder compared to controls. On the whole sample, difficulty to disengage from diurnal and nocturnal sleep -related stimuli were related mostly to higher arousal rating of sleep -related stimuli and insomnia severity. Higher arousal rating for sleep -related stimuli mediates the relationship between difficulty disengaging and insomnia severity. Limitations: The cross-sectional nature of the study. Conclusions: We provide first initial evidence for an attentional bias characterized by on one side, avoidance for diurnal sleep -related stimuli and on other side, disengagement for both diurnal and nocturnal sleep -related stimuli in patients with insomnia. Disengagement difficulties for both diurnal and nocturnal sleep -related stimuli indirectly affected insomnia severity through arousal elicited by these stimuli. It appears important to develop and apply attentional bias modification training therapeutic interventions that can effectively reduce sleep -related arousal and attentional biases.