Aberrant White Matter Microstructure in Depressed Patients with Suicidality

Area of Science:

• Neuroimaging
• Psychiatry
• Neuroscience

Background:

• Depression affects millions globally, with suicide as a severe outcome.
• While brain alterations in depression are known, white matter (WM) microstructure changes related to suicidality require further investigation.

Purpose of the Study:

• To investigate structural alterations in white matter (WM) microstructure associated with suicidality in depressed patients.
• Utilize automated fiber quantification (AFQ) to analyze diffusion properties of WM tracts.

Main Methods:

• A cross-sectional study involving 45 depressed patients without suicidality (DS-), 53 depressed patients with suicidality (DS+), and 59 healthy controls (HC).
• Magnetic resonance imaging (MRI) with a 3.0T scanner and a single-shot echo-planar imaging sequence was employed.
• Diffusion properties (fractional anisotropy, mean diffusivity, axial diffusivity, radial diffusivity) of 18 specific WM tracts were calculated using AFQ.

Main Results:

• Significant differences in diffusion properties were observed in callosum forceps, left inferior fronto-occipital fasciculus (IFOF), right anterior thalamic radiation (ATR), and left cingulum cingulate between DS- and DS+ groups.
• Mean diffusivity (MD) of the right ATR positively correlated with Hamilton Depression Rating Scale (HAMD) scores.
• Axial diffusivity (AD) of the right ATR, MD and radial diffusivity (RD) of callosum forceps minor, and RD of the left IFOF positively correlated with suicide item scores on the HAMD.

Conclusions:

• Decreased WM tract integrity in the callosum forceps, IFOF, and ATR is associated with suicidality in depression.
• These findings highlight the involvement of frontal cortex and limbic system white matter pathways in the neurobiology of suicidality in depression.