AHI1 and major depressive disorder: Previous studies reported the relationship between AHI1 polymorphism and psychiatric disorders, including schizophrenia, autism spectrum, major depressive disorder and bipolar disorder (Alvarez Retuerto et al. 2008; Ingason et al. 2010; Torri et al. 2010; Porcelli et al. 2014; Ren et al. 2016).