Brain Structural Network Connectivity of Formal Thought Disorder Dimensions in Affective and Psychotic Disorders

Area of Science:

• Neuroscience
• Psychiatry
• Medical Imaging

Background:

• Formal thought disorder (FTD) is a psychopathological syndrome observed in schizophrenia (SZ), major depressive disorder, and bipolar disorder.
• The relationship between structural white matter alterations and FTD dimensions across these disorders is not well understood.

Purpose of the Study:

• To identify psychopathological dimensions of FTD.
• To investigate the association between these FTD dimensions and the brain's structural connectome.
• To explore potential transdiagnostic neural mechanisms underlying FTD.

Main Methods:

• Factor analysis of FTD items from symptom scales in 864 patients (major depressive disorder, bipolar disorder, SZ).
• Reconstruction of the structural brain connectome using MRI (T1- and diffusion-weighted imaging).
• Linear regression and network-based statistics to analyze associations between FTD dimensions and white matter subnetworks.

Main Results:

• Three FTD dimensions were identified: disorganization, emptiness, and incoherence.
• Disorganization and incoherence correlated with global brain dysconnectivity.
• Specific white matter subnetworks were associated with FTD dimensions of disorganization and emptiness, implicating speech-related brain regions.

Conclusions:

• White matter subnetwork dysconnectivity is associated with FTD dimensions across major depressive disorder, bipolar disorder, and schizophrenia.
• These findings suggest shared neuropathological pathways for FTD, particularly in speech-related brain areas.
• This research supports transdiagnostic, psychopathology-informed approaches to understanding the pathogenesis of FTD.