NPY and major depressive disorder: It would be reasonable to expect group differences in default mode network connectivity, as low-NPY is associated with the development of depression (Mickey et al., 2011), and stronger default mode network connectivity has been reported in subjects with depression (Wang et al., 2016; Helm et al., 2018), and low-NPY status has been associated with greater activation of medial prefrontal cortex (Mickey et al., 2011).