This research investigates the relationship between changes in white matter microstructure and cognitive decline in individuals with major depressive disorder (MDD). The study follows a large cohort of participants with MDD and healthy controls over a two-year period, analyzing cognitive performance and white matter integrity using neuropsychological tests and diffusion-weighted imaging. The authors found that individuals with MDD showed a greater decline in white matter integrity in the superior longitudinal fasciculus, a brain region important for information processing, compared to healthy controls. Furthermore, the study found a robust association between cognitive decline and the decline in white matter integrity across all participants. While changes in white matter integrity did not mediate the relationship between disease course and cognitive performance, the authors suggest that this could be due to the relatively short follow-up period and the mild disease course in their sample. The study emphasizes the crucial role of white matter microstructure and disease progression in depression-related cognitive dysfunction, highlighting the need for future research to investigate these complex relationships further.

STUDY:
Flinkenflügel K, Meinert S, Hirtsiefer C, Grotegerd D, Gruber M, Goltermann J, Winter NR, Stein F, Brosch K, Leehr EJ, Böhnlein J. Associations between white matter microstructure and cognitive decline in major depressive disorder versus controls in Germany: a prospective case-control cohort study. The Lancet Psychiatry. 2024 Nov 1;11(11):899-909.