Segregated neural representation of psychological and somatic-vegetative symptoms in severe major depression

Objective: The Beck Depression Inventory (BDI) is probably the most widely used depression scale. It has been suggested that it contains a two-factor structure measuring cognitive-affective (i.e. psychological) and somatic-vegetative depressive symptoms. In this study we aim to evaluate these factors by probing for their neural correlates. Methods: Neural responses evoked by emotional perception, relative to an emotional judgment task, were measured using functional magnetic resonance imaging (fMRI) in 20 medication-free patients with severe MDD. Psychological and somatic-vegetative symptoms were evaluated with the BDI. Results: Psychological symptoms correlated with signal changes in the dorsomedial and right ventrolateral prefrontal cortex, while somatic-vegetative symptoms correlated with signal changes in the pre-genual anterior cingulate cortex. Conclusions: These preliminary findings demonstrate segregated neural representation of psychological and somatic-vegetative symptoms of MDD in different cortical regions. Thus, our results indicate that the two-factor structure of the BDI is related to distinct neural correlates.