Depression and anxiety mediate the relationship between frontotemporal white matter integrity and quality of life in distressed young adults.

Depression and anxiety have been linked to poor quality of life (QoL) - one's subjective perception of relationships, physical health, daily functioning, general sense of well-being and life satisfaction. Elucidating abnormal white matter microstructure associated with mood and other symptoms and QoL is important to facilitate treatment. Ninety-six young adults (18-25 years old) seeking help for psychological distress, irrespective of presence or absence of psychiatric diagnosis completed diffusion weighted and anatomical scans, clinical and behavioral measures, and QoL assessment. We examined relationships between diffusion imaging properties in major white matter tracts involved in emotion processing and regulation, symptoms, and QoL. Depression and general distress levels fully mediated the relationship between fractional anisotropy (FA), an indirect index of fiber collinearity, and radial diffusivity (RD), an index sensitive to axonal/myelin damage, in right uncinate fasciculus and QoL. The relationship between reduced FA (and increased RD) in right uncinate fasciculus and poor QoL was explained by greater severity of depression and general distress. These findings underscore the role of white matter microstructure in right uncinate fasciculus in relation to depressive and general distress symptoms and, in turn, QoL. Importantly, they suggest that measures of white matter microstructure in this tract can be used as putative objective markers of emotion dysregulation, to inform and monitor the impact of interventions to reduce affective symptoms and improve QoL in young adults.