DRD3 and Anxiety: The Dopaminergic System: After challenging the dopaminergic system with the antagonist sulpiride and the agonist pramipexole, patients with SAD showed heightened anxiety symptoms but, after SSRI treatment (with remission of anxiety symptoms), patients showed an attenuated impact of pramipexole, suggesting a degree of dopamine D3 receptor desensitization after SSRI therapy [61].