GRIK2 and major depressive disorder: Additional examples include schizophrenia for RELN, GluR6, GRIN2A, GRIN2B, and CNTNAP2 (Bah et al., 2004; Friedman et al., 2008; Shifman et al., 2008; Demontis et al., 2011), childhood absence epilepsy for GABRB3 (Feucht et al., 1999), ADHD and depression for 5-HTT (Manor et al., 2001; Caspi et al., 2003), and major depression for TPH2 (Zill et al., 2004).