Together with the current DTI results, it appears that the LQS subtype may represent a ‘reactive’ MDD subpopulation mainly characterized by monoamine and amino acid neurotransmitter abnormalities in stress processing-related temporal-occipital network; whereas the HSD subtype is related to ‘endogenous’ dysfunction of BCAA and energy metabolism, hyperconnectivity and microstructural abnormalities in the limbic-paralimbic network. This evidence concerns the gene CHST3 and major depressive disorder.