Brain Scans Reveal Shared and Distinct Antidepressant Effects Within Two Weeks

Brain scans from 386 adults with major depressive disorder (MDD) show early, shared changes in functional connectivity within a visual, precuneus, thalamus system, observed regardless of treatment type or symptom improvement, according to researchers at Stanford University, UT Austin and colleagues. Published in Nature Mental Health, the study used resting-state fMRI to compare pre- and post-treatment scans after one or two weeks of placebo, sertraline, or escitalopram.

Xiaoyu Tong, Gregory A. Fonzo and team identified distinct patterns: placebo-related symptom improvement correlated with changes in striatal and attention networks, while antidepressant-specific effects involved the amygdala, midcingulate and orbitofrontal cortices, and cerebellum, but only in a subset of treated patients. These drug-specific signatures could be predicted using a placebo response model for nonresponders.

The authors suggest these findings clarify mechanisms of antidepressant action and may support future individualized treatment selection using early brain imaging.