Nitrous Oxide Alters Functional Connectivity in Medial Limbic Structures in Treatment-Resistant Major Depression.
medRxiv : the preprint server for health sciences August 17, 2024 Charles R Conway, Ben Julian A Palanca, Thomas Zeffiro et al. preprint
Nitrous oxide (N2O) reduces functional connectivity in mood-related brain networks in people with treatment-resistant major depression (TRD) but increases connectivity in healthy controls. In a crossover trial, 14 TRD patients and 16 healthy controls received one-hour inhalations of 50% N2O or placebo. Resting-state fMRI scans before, 2 hours, and 24 hours after inhalation showed that N2O progressively decreased connectivity in TRD patients across five brain networks (salience, default mode, reward, cingulo-opercular, and the dorsal nexus), while increasing connectivity in controls. The findings suggest N2O's antidepressant effects involve specific alterations in depressed brains.