PDE11A single nucleotide polymorphisms are associated with major depressive disorder (MDD) (Cabanero et al., 2009; Luo et al., 2009; Wong et al., 2006), suicide risk (Coon et al., 2013), sleep quality (Jones et al., 2019), antidepressant response in patients with MDD (Luo et al., 2009; Wong et al., 2006) (but see (Cabanero et al., 2009; Perlis et al., 2010)), and lithium response in patients with bipolar disorder (Couzin, 2008; Kelsoe, 2010; Mertens et al., 2015). This evidence concerns the gene PDE11A and major depressive disorder.