Population-based screening for Major Depressive Disorder requires balancing sensitivity against specificity to avoid overwhelming clinical resources. Existing screening pipelines often rely on self-report questionnaires and do not integrate neuroimaging with clinical phenotypes. We evaluate multimodal decision-level fusion that combines resting-state fMRI connectivity graphs with clinical measures (sleep quality, anxiety, age) for depression screening. Using the Cam-CAN cohort (N=652; ~15% reporting depression requiring treatment), we compare graph neural network (GNN) architectures and fusion policies under 5-fold cross-validation with nested validation. A Graph Isomorphism Network with Risk-Union Fusion (RUF) achieves AUC of 0.85 with 62% sensitivity at 90% specificity, supporting sensitivity-oriented first-stage screening by flagging risk detected by either modality. Integrated Gradients identifies connectivity biomarkers localizing predominantly to temporal and cingulate regions. These results support interpretable multimodal integration for population-based depression screening.
R. Yu, M. Katzman, A. Greifenberger, E. Toumeh, S. Lokuge, T. Sternat, X. Qin, and L. Wang. Interpretable Multimodal Depression Screening on Cam-CAN via fMRI Connectivity Graph Neural Networks and Clinical Measures. Manuscript submitted to the Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC 2026).