HTR1A and major depressive disorder: Disturbances in the 5HT1A and 5HT2A receptors have been implicated in the development of stress-related illness such as major depressive disorder (MDD) (Stockmeier, 2003; Noro et al., 2010), and enhancing 5-HT1A receptor gene expression and activity predicts a favorable outcome for anti-depressant action (Albert and Francois, 2010).