Emotion regulation difficulties in the relation between stress-related insomnia symptoms and brain response to emotional faces: An fMRI study

The aim of the current study was to investigate whether the experience of insomnia symptoms per se and symptoms of insomnia due to stress are associated with an increased brain response to the presentation of emotional faces. In addition, we also examined whether the effect of these sleep difficulties on emotional reactivity at the brain level depends on the experience of emotion regulation (ER) difficulties. The current sample consisted of 37 individuals (20 females, 17 males) selected from a larger group of 120 respondents who completed a survey about sleep problems and ER difficulties. Our results indicate that the tendency to experience stress-related insomnia symptoms but not insomnia symptoms per se modulates brain responses to emotional facial expressions, especially in areas of the parietal cortex, insula, and surrounding opercular voxels. Furthermore, difficulties in ER might play an important role, as the effect of stress-related insomnia symptoms on most of these brain regions disappears when controlling for difficulties in ER. However, an effect in the insula was maintained during the presentation of angry faces, suggesting that stress-related insomnia symptoms may increase the brain response to anger in the insula relatively independent from difficulties in ER. These findings suggest that individuals affected by stress-related insomnia symptoms show an enhanced brain response when presented with emotional stimuli (either positive or negative) in brain areas associated with hyperarousal, which could represent a possible ER deficit in these individuals. Thus, interventions that focus on targeting ER difficulties might be effective in reducing the hyperarousal state in individuals affected by stress-related insomnia symptoms.