DRD2 and major depressive disorder: To illustrate, symptoms such as nausea, vomiting and depression are likely to be produced due to binding of sibutramine to targets such as SLC6A3 and SLC6A4 and subsequent perturbation of pathway involving HTR2C (anxiety), HTR2A (anxiety), DRD2 (nausea and vomiting), COMT (nausea and vomiting), and MAOA (depression) (File E in S1 File).