This observational study examined brain structure in 645 medication-free individuals with major depressive disorder currently experiencing a depressive episode. These participants were compared to 645 matched healthy controls across 11 sites in the COORDINATE-MDD consortium. The researchers measured the brain age gap, which estimates how much a person's brain looks older than their actual age based on MRI scans.
The main finding was that major depressive disorder was associated with a significantly elevated brain age gap. However, this difference was not present before the mid-30s. The gap grew progressively larger with age, reaching about 6.85 years in people aged 55 and older. Specific brain regions contributed to these differences, though the study did not detail which ones.
The study also looked at secondary outcomes like regional volumes and links to cognitive impairment or suicide attempts. Safety concerns were not reported because this was an observational scan study without interventions. Readers should take away that accelerated brain aging is not a uniform feature of depression. Instead, it seems more strongly expressed in a specifically clinically vulnerable disease phenotype. More research is needed to understand these findings fully.