Inflammation is implicated in the aetiology of major depressive disorder (MDD) and is known to affect brain microstructure: e.g. the striatum as found with neurite orientation dispersion and density imaging (NODDI) and quantitative magnetization transfer (qMT) imaging. Further, individuals with high inflammation (C-reactive protein (CRP)>3mg) respond less well to antidepressants. The BIOmarkers of DEPression (BIODEP) multi-centre study is aiming to characterise the inflamed MDD phenotype. We report across-site data harmonization and interim results demonstrating a negative correlation between the water fraction content (NODDI) and CRP within the ventral striatum. Multi-modal imaging results (qMT, multi-component relaxometry) across the full cohort will be reported.