Effect of lifetime exposure to depression on brain structure and function in the UK Biobank

Abstract

Background: Depression is a common mental health condition in the general population. Whereas various neuroimaging studies have reported altered activity and structural impairments in depression, several recent meta-analyses only found small or inconsistent effects of depression. Different operational inclusion criteria and processing methodologies may contribute to these discrepancies. We addressed these issues by systematically testing for the effects of different criteria of lifetime exposure to depression on functional and structural neuroimaging measures in the UK biobank cohort. Methods: We included 36,359 participants (20,794 lifetime depression and 15,565 healthy individuals) from the UK biobank. Six increasingly conservative groups of lifetime depression were defined based on the six available depression criteria from meeting only one to more restrictive meeting all six criteria. We tested the effect of these definitions on voxel-wise measures of local functional activity, global connectivity and gray matter volume. Results: Across all depression definitions, individuals with lifetime depression displayed regionally consistent decreases in local functional activity alterations in sensorimotor cortex but not in global connectivity and gray matter volume alterations. More restrictive definitions and antidepressant usage resulted in most pronounced alterations. Conclusion: Lifetime exposure to depression is associated with robust functional changes with more restrictive criteria revealing more pronounced alterations. Different inclusion criteria of depression may strongly contribute to the substantial variation of imaging findings reported in the literature.