White matter microstructure in body dysmorphic disorder and its clinical correlates

Area of Science:

• Neuroimaging
• Psychiatry
• Neuroscience

Background:

• Body dysmorphic disorder (BDD) involves preoccupation with perceived appearance flaws, causing distress and disability.
• Previous research identified functional abnormalities in visual, frontostriatal, and limbic systems in BDD.
• White matter microstructure connecting these systems in BDD remains understudied.

Purpose of the Study:

• To investigate white matter microstructure in individuals with BDD using diffusion-weighted MRI.
• To explore the relationship between white matter integrity, symptom severity, and insight in BDD.

Main Methods:

• Diffusion-weighted magnetic resonance imaging (MRI) was used in 14 individuals with BDD and 16 healthy controls.
• Probabilistic tractography and tract-based spatial statistics analyzed white matter tracts.
• Measures of white matter microstructure included fractional anisotropy (FA) and mean diffusivity (MD).

Main Results:

• Poor insight in BDD correlated with altered FA, linear anisotropy (c(l)), and mean diffusivity (MD) in specific white matter tracts (inferior longitudinal fasciculus, forceps major).
• While not statistically significant, the BDD group showed trends towards altered FA and c(l) in the inferior longitudinal fasciculus and inferior fronto-occipital fasciculus, and higher FA/c(l) in the forceps major.
• This is the first diffusion-weighted MRI study examining white matter in BDD.

Conclusions:

• Results suggest a link between impaired insight in BDD and white matter fiber disorganization.
• These findings highlight potential microstructural alterations in tracts connecting visual processing with emotion and memory systems in BDD.