Cross-disorder comparison of Brain Structures among 4,842 Individuals with Mental Disorders and Controls utilizing Danish population-based Clinical MRI Scans

Large-scale mega-analyses of worldwide combined Magnetic Resonance Imaging (MRI) studies have demonstrated brain differences between individuals with mental disorders and controls. However, the potential of large-scale observational studies using population-based clinical MRI data remains unexplored. We analyzed clinical MRI data from 23,545 patients in the Capital Region of Denmark. 2,776 patients with mental disorders and 2,066 non-psychiatric controls fulfilled our inclusion and exclusion criteria. Patients with mental disorders exhibited known atrophy patterns in the thalamus (d=−0.303) and amygdala (d=−0.245), with larger ventricles (d=0.277), and thinner insula (d=−0.191), all p<0.0001. Analysis across all ROIs revealed widespread cortical thinning (d=−0.207), especially in the middle temporal (d=−0.242) and temporal pole (d=−0.241) regions, and increased cerebrospinal fluid (d=0.268). For volumetric measurements, findings were consistent across different inclusion and exclusion criteria but varied for cortical thickness measurements. Utilizing this currently largest population-based MRI cohort for mental disorders, we demonstrate that clinical MRI scans can detect brain structural differences among patients with mental disorders in real-world clinical settings, aiding in the stratification of patients without mental disorders. Integrating large-scale clinical MRI data with electronic health records holds substantial potential for improved patient stratification and tracking of disease progression for future longitudinal cross-disorder studies, bridging real-world MRI data with clinical trajectories for further biological subgrouping.