In this scenario, targeting TAAR1 could lead to novel approaches for the treatment of several disorders [18,19,20] including not only schizophrenia but also depression, attention deficit hyperactivity disorder, addiction [21], and metabolic diseases by means of agonist compounds, and Parkinson’s disease by antagonists [22,23,24,25,26,27]. This evidence concerns the gene TAAR1 and major depressive disorder.