Regarding depression, while findings from some small, earlier studies suggested that depressed patients may have a higher negative feedback sensitivity on the PRL task [61, 62], the measure used to conclude this (correct-loss shift proportion) would also have been influenced by reward sensitivity, and the findings could hence have been explained by the reduced reward sensitivity that has been repeatedly reported in depression [28, 29, 63–65]. This evidence concerns the gene PRL and major depressive disorder.