Effect of Ketamine on Reward Processing in Depressive Disorders: A Systematic Review of Neuroimaging Studies
CNS Spectrums March 10, 2026 Halima Faisal, Gia Han Le, Angela T H Kwan et al.
Ketamine rapidly alters brain reward circuitry in people with major depressive disorder, particularly in fronto-striatal and limbic networks. In a synthesis of 13 neuroimaging studies involving 623 participants (482 with depression, 141 controls), intravenous ketamine (typically 0.5 mg/kg over 40 minutes) changed resting-state connectivity in ventral striatal-prefrontal and default mode, salience, and executive networks within 2 to 48 hours, with some effects lasting up to 10 days. Task-based imaging showed altered ventral striatal responses during reward anticipation and feedback, and changes in medial prefrontal activity during emotion processing. PET scans indicated increased prefrontal-cingulate metabolism and region-specific serotonin receptor binding changes. Few studies directly measured anhedonia, suggesting the findings reflect broader antidepressant mechanisms.