Major depressive disorder (MDD) is a complex and heterogeneous disorder in which clinical symptoms can widely differ among patients. Neurovegetative symptoms, i.e. decreased or increased appetite, changes in body weight and sleep disturbances, described as 'melancholic' or 'atypical' features of a depressive episode, are the most variable symptoms among patients with MDD. We hypothesized biomarkers differences underlying this neurovegetative variability in major depression.