Voxel-based morphometry imaging studies in major depression

Major depressive disorder is a frequent psychiatric illness with increasing incidence and heterogeneous course, which affects all the adults’ lifespan. Clinical outcome and treatment response can vary a lot among patients; therefore, there has been an increasing demand for biological markers for early identification, clinical course prediction, and treatment response to this disease. In this context, imaging techniques offer a valid tool for the biological characterization of the disease. In particular magnetic resonance imaging with voxel-based morphometry analysis performs wide investigations of whole-brain alterations with an atheoretical approach. This technique allowed the identification of an altered network involving medial prefrontal cortex, anterior cingulate, insula, and limbic areas, such as hippocampus and amygdala. This network is involved in emotional processing, cognitive control on affectiveness and mnesic abilities. These areas, particularly limbic ones, have been observed by imaging studies to be responsive to pharmacological treatment; also, preserved volumes in these areas are indicators of better clinical response. According to these observations, imaging technique can be considered a valid application for a thorough comprehension of MDD features and to follow-up clinical response in this group of patients.