These connections place the Hb in a central position for the regulation of motivated behaviors, and thus has been implicated in the pathophysiology of several disorders, such as autism spectrum disorder (ASD) (6), depression (7, 8), bipolar disorder (8–10), and schizophrenia (10, 11), as well as neuropsychiatric symptoms, such as aggressive behaviors (12, 13). This evidence concerns the gene GSTM1 and major depressive disorder.