White matter fiber microstructure is associated with prior hospitalizations rather than acute symptomatology in major depressive disorder

Abstract

Background Eighty percent of all patients suffering from major depressive disorder (MDD) relapse at least once in their lifetime. Thus, understanding the neurobiological underpinnings of the course of MDD is of utmost importance. A detrimental course of illness in MDD was most consistently associated with superior longitudinal fasciculus (SLF) fiber integrity. As similar associations were, however, found between SLF fiber integrity and acute symptomatology, this study attempts to disentangle associations attributed to current depression from long-term course of illness. Methods A total of 531 patients suffering from acute (N = 250) or remitted (N = 281) MDD from the FOR2107-cohort were analyzed in this cross-sectional study using tract-based spatial statistics for diffusion tensor imaging. First, the effects of disease state (acute v. remitted), current symptom severity (BDI-score) and course of illness (number of hospitalizations) on fractional anisotropy (FA), mean diffusivity (MD), radial diffusivity (RD), and axial diffusivity were analyzed separately. Second, disease state and BDI-scores were analyzed in conjunction with the number of hospitalizations to disentangle their effects. Results Disease state (pFWE < 0.042) and number of hospitalizations (pFWE< 0.032) were associated with decreased FA and increased MD and RD in the bilateral SLF. A trend was found for the BDI-score (pFWE > 0.067). When analyzed simultaneously only the effect of course of illness remained significant (pFWE < 0.040) mapping to the right SLF. Conclusions Decreased FA and increased MD and RD values in the SLF are associated with more hospitalizations when controlling for current psychopathology. SLF fiber integrity could reflect cumulative illness burden at a neurobiological level and should be targeted in future longitudinal analyses.

Desynchronized white matter function and structure in drug-naive first-episode major depressive disorder patients

“…We speculate that it may be due to the higher HAMD scores, the longer duration of illness and the mixed recurrent patients of MDD in Zeng’s study. Previous study has concluded that lower FA values in the SLF were related with more hospitalizations and that SLF fiber integrity may reflect the cumulative disease burden in MDD ( 66 ). It also suggested that the damage in WM structures did not occur in the early stage of the disease, but emerged as the disease progresses further.…”

Association of brain white matter microstructure with cognitive performance in major depressive disorder and healthy controls: a diffusion-tensor imaging study

“…Especially association and commissural white matter fibers responsible for higher cognitive functioning, continue to develop throughout adolescence to early and middle adulthood [36,63]. This prolonged development is the underlying basis for white matter plasticity, which in turn would be necessary for environmental and (epi-) genetic factors to in turn influence fiber structure [63][64][65].…”