Is first episode mania associated with grey matter abnormalities? We are not sure!

With great interest, we have read the recent paper by Keramatian and colleagues entitled "Grey Matter Abnormalities in First Episode Mania: A Systematic Review and Meta-analysis of Voxel-Based Morphometry Studies" in Bipolar Disorders1 . The authors systematically reviewed 15 voxel-based morphometry (VBM) studies and observed heterogeneous findings regarding the brain regions affected and the direction of grey matter (GM) alterations (decreases/increases) as well as statistically non-significant alterations in patients with first episode mania (FEM) relative to healthy controls.