Reduced cortical surface area globally and in reward-related cortex is associated with elevated depressive symptoms in preschoolers

Abstract

Background: Elevated depressive symptoms in early childhood strongly predict depression onset in youth. Nevertheless, little is known about the neural correlates of these symptoms, information that is key for understanding the early development of depression. As a result, the present study conducted a novel investigation of the association between cortical structure and depressive symptoms in preschoolers.

Methods: Forty-six preschool age children (M_age = 5.90, SD = 0.75), some (N = 15) at high risk for depression, participated in the study. Data included parent-report of child depressive symptoms and measures of child whole brain and regional cortical structure acquired via 3T MRI.

Results: After adjustment for maternal depression, socio-economic status, child age, child sex, and intracranial volume, reduced total cortical surface area and reduced surface area of the lateral orbitofrontal cortex were associated with elevated depressive symptoms. Cortical thickness was not associated with depressive symptoms.

Limitations: The present data are cross-sectional, limiting any causal interpretations.

Conclusions: Results suggest that reduced cortical surface area, rather than thickness, is a neural correlate of depressive symptoms in preschoolers. Findings highlight the importance of surface area in reward processing regions (i.e., lateral orbitofrontal cortex) in particular. The present results provide novel insight into early emerging associations between brain structure and features of depression in young children and underscore early childhood as an important developmental period for understanding depression.

Keywords: Depression; Early childhood; Structural MRI; Surface area.