White Matter Integrity and Subclinical Depression: A Diffusion Tensor Imaging Study

Abstract

Major Depressive Disorder (MDD) is characterized by the persistent presence of at least five depressive symptoms over a two-week period . These symptoms must include either depressed mood, or loss of interest or pleasure. Early identification, and ultimately treatment, of depression may be accomplished by identifying neural markers of individuals at risk for MDD, including those with subclinical depressive symptoms . Neuroimaging studies have shown that MDD is associated with impairments to integrity in white matter tracts such as the corpus callosum and internal capsule . However, it is unclear whether these same structures also are disrupted in subclinical depression . The present study sought to examine this question through utilizing diffusion tensor imaging to assess white matter integrity as a function of Geriatric Depression Scale Short Form (GDS-SF) scores . Using a median split of GDS-SF scores, statistical analyses revealed no difference in white matter integrity between low risk and high risk depression groups. However, there was a nonsignificant trend (p=0 .072) such that higher GDS-SF scores were associated with decreased white matter integrity localized to the corpus callosum, right internal capsule, left cingulum, external capsule and fornix . This finding extends previous research on MDD by providing evidence for similar neural correlates of subclinical depression . This may provide insight into the development of MDD and ultimately aid diagnostic and treatment efforts with early identification and intervention.