DRD3 and major depressive disorder: However, the only anti-parkinsonian therapy that has been shown in a randomized controlled trial to improve depressive symptoms in PD is pramipexole (patients in the pramipexole trial had lower baseline BDI scores of 18.7-19.5),40 which has been shown to bind with high affinity to dopamine D3 receptors in the prefrontal cortex, amygdala, and medial and lateral thalamus (all known to have some relationship with depression).41