Changes in Brain Glucose Metabolism After DMT and Harmine Adminstration: A human [¹⁸F]FDG-PET Study

Classical psychedelics like DMT modulate consciousness via serotonergic pathways and show therapeutic promise. This FDG-PET study examined how oral DMT with harmine affects brain glucose metabolism (CMRglc) in 14 healthy males using a placebo-controlled crossover design. Global CMRglc increased by 12% during the DMT+harmine condition, with prominent effects in the default mode and frontoparietal networks. Increases were also seen in attention networks. Harmine plasma levels correlated with global CMRglc. These findings suggest that heightened brain energy metabolism is a key feature of the psychedelic state and may represent a common neuroenergetic signature across serotonergic psychedelics.