Research paperWhite matter microstructure in boys with persistent depressive disorder

•White matter alterations found in specific tracts in boys with persistent depressive disorder.•Boys with depression exhibited lower FA in uncinate, inferior fronto-occipital and cerebrospinal tracts.•White matter in left uncinate associated with self-reported symptoms of depression.•Alterations in white matter may contribute to maintenance and recurrence of depressive symptoms in children.

BackgroundPersistent depressive symptoms in children and adolescents are considered a risk factor for the development of major depressive disorder (MDD) later in life. Previous research has shown alterations in white matter microstructure in pediatric MDD but discrepancies exist as to the specific tracts affected. The current study aimed to improve upon previous methodology and address the question whether previous findings of lower fractional anisotropy (FA) replicate in a sample of children with persistent depressive disorder characterized by mild but more chronic symptoms of depression.MethodsWhite matter microstructure was examined in 25 boys with persistent depressive disorder and 25 typically developing children. Tract specific analysis implemented with the Diffusion Tensor Imaging - ToolKit (DTI-TK) was used to probe fractional anisotropy (FA) in eleven major white matter tracts.ResultsClusters within the left uncinate, inferior fronto-occipital and cerebrospinal tracts showed lower FA in the clinical group. FA in the left uncinate showed a negative association with self-reported symptoms of depression.ConclusionsThe results demonstrate lower FA in several white matter tracts in children with persistent depressive disorder. These findings support the contention that early onset depression is associated with altered white matter microstructure, which may contribute to the maintenance and recurrence of symptoms.