EGR1 and major depressive disorder: EGR1 has been implicated in mediating a variety of behaviors that are dysregulated in MDD, including learning and memory, fear conditioning, drug addiction, and social interaction (Cole et al., 1989; Ressler et al., 2002; Malkani et al., 2004; Valjent et al., 2006; Stack et al., 2010).