A major international study, published this week in JAMA Psychiatry, has identified a powerful new brain-based biomarker for Major Depressive Disorder (MDD), marking a potential turning point in how depression is diagnosed and treated. The study used regional cerebral blood flow (RCBF) data measured by brain SPECT imaging to validate a reproducible, regionally specific pattern of hypoperfusion in the brains of individuals suffering from depression.

This landmark research demonstrates that functional brain changes—specifically decreased blood flow—are more accurate markers of depression than structural brain changes like cortical thinning, which have historically shown weak and inconsistent associations.

The study examined more than 15,000 participants across four major databases, including the UK Biobank, ENIGMA Consortium, Amish Connectome Project, and Amen Clinics Inc. Notably, the blood flow patterns from SPECT scans aligned strongly with novel MRI-based measures of brain function (ReHo), confirming that decreased activity in the cingulate, prefrontal, and temporal lobes is a hallmark of depression.

Even more importantly, the study found that these blood flow deficits were strongly correlated with the severity of depressive symptoms, opening the door for precision diagnostics and individualized treatment plans based on imaging biomarkers.