251. Dopamine Release in Treatment-Naïve Major Depressive Disorder: A [11C]-(+)-PHNO Positron Emission Tomography Study

Major depressive disorder (MDD) and anhedonia have been associated with mesolimbic dopamine (DA) system dysfunction, but neuroimaging studies using nonselective D2/D3 antagonist radioligands have yielded mixed results. The current study used [11C]-(+)-PHNO, an agonist radioligand with preferential selectivity for D3 over D2 receptors and high sensitivity to the DA-releasing effects of amphetamine, to examine DA function in...