DRD1 dysfunction in the LHb increases anxiety-like behavior but decreases depressive-like behavior, and impairs aversive learning in rats, suggesting that proper activation of DRD1 in LHb is important for this processing, and manipulation of LHb neurons through DRD1 may be a target for the treatment of depression (Proulx et al., 2014). Here, DRD1 is linked to major depressive disorder.