Neuroanatomical basis of harm avoidance personality traits in major depressive disorder

Abstract Background : Behavioral inhibition, referred to as the harm avoidance (HA) trait, has been deemed a vulnerability factor for major depressive disorder (MDD). Previous studies tried to find brain structural biomarkers of HA by assessing the relationship between interindividual variability in this trait and brain morphology. However, only healthy participants were recruited for these studies, and the results were heterogeneous. Methods : To clarify the neural link between HA and MDD, we obtained magnetic resonance imaging data from the brains of 331 healthy people and 89 patients with MDD. Voxel-based morphometry (VBM) analyses were conducted to identify brain regions in which the gray matter volume was correlated with the HA score across participants and was simultaneously reduced in MDD patients. Results : We found that the ventral part of the medial preferential cortex (vMPFC) fulfilled these criteria. Limitations : The majority of the patients in this study were medicated with antidepressants. Conclusions : The present finding suggests that reduced gray matter volume in this region is the neuropathology of high HA observed among MDD patients and might be the underlying reason why people with high HA are vulnerable to developing depression. Our findings may contribute to a deeper understanding of the neuropathology of MDD and provide insight into the brain regions of interest for predicting the development of the illness in the future.