Elsevier Jun 20 2025 A novel study aimed at disentangling the neurological underpinnings of depression shows that multiple brain profiles may manifest as the same clinical symptoms, providing evidence to support the presence of both one-to-one and many-to-one heterogeneity in depression. The findings of the study in Biological Psychiatry , published by Elsevier, highlight the layered and complex interactions between clinical symptoms and neurobiological sources of variation. John Krystal, MD,