Out of the 14 receptors for serotonin (5-hydroxytryptamine, 5-HT), the inhibitory 5-hydroxytryptamine1A (5-HT1A) and 5-hydroxytryptamine1B (5-HT1B) receptors have attracted particular attention as potentially involved in the pathophysiology of depression and as putative targets in the pharmacologic treatment of MDD (Moret and Briley 2000; Murrough et al. 2011b; Murrough and Neumeister 2011; Ruf and Bhagwagar 2009; Sari 2004; Savitz et al. 2009; Tiger et al. 2014). The gene discussed is HTR1A; the disease is major depressive disorder.