RecruitingPhase 2Drug trialPharmaco-Neuroimaging Studies of Approach/Avoidance Behaviors and Post-Mortem Studies: Pharmacological ManipulationThe study will investigate whether a nociceptin receptor antagonist will normalize neural and behavioral processes of approach/avoidance decision-making in unmedicated individuals with major depressive disorder (MDD) and anxiety disorders. More specifically, the study aims to investigate dysregulation within (1) corticostriatal-midbrain circuitry and (2) nociceptin/orphanin FQ peptide and the nociceptin receptor (NOPR).