Attentional-cognitive processes allow the association between depressive symptoms and leftward visuospatial bias to emerge in middle-aged adults

Background: The right hemisphere is dominant for spatial attention and is implicated in negative emotional and self-related information processing. Right hemisphere engagement produces a leftward visuospatial bias, whereas reduced engagement a rightward bias. Using a cross-sectional design, we investigated the relationship between subclinical depressive symptoms (DS) and visuospatial bias in middle-aged adults and whether attentional-cognitive processes moderate this relationship. Methods: Forty right-handed volunteers, divided into two groups (DS: N = 20, 15 females, mean age = 51.700 years, SD = 7.596; no-DS: N = 20, 14 females; mean age = 50.750 years, SD = 7.806) based on their Beck Depression Inventory-II scores, completed a line bisection task (visuospatial bias), a Complex Visual Reaction Times test (inhibitory control, speed of processing) and a Symbol Digit Modalities Test (sustained attention, working memory). Results: No-DS participants exhibited a rightward bias, whereas DS participants a leftward bias (F = 6.378, p < 0.05). The relationship between DS and the leftward bias was present only at medium-to-high sustained attention and working memory (B = -0.00133, β = -0.478), and speed of processing (B = 0.00007, β = 0.411), but not inhibitory control. Conclusion: The rightward bias in the absence of DS is consistent with an age-related reduction in right hemisphere dominance for spatial attention. The leftward bias in the presence of DS is consistent with attentional tendencies toward negative emotional and self-related information, which have been associated, at least in part, with the right hemisphere engagement. This relationship emerged only when attentional-cognitive functioning was preserved.