GSTM1 and treatment resistant depression: In this study, we examined how FC of the Hb and NAc, key nodes of reward circuitry implicated in the neurobiology of depression (Gold & Kadriu, 2019; Proulx et al., 2014; Yang et al., 2018), are perturbed by SKI treatment in participants with TRD, and associate with improvements in mood and anhedonia.