NR4A2 has been implicated in drug addiction (Bannon et al., 2002; Horvath et al., 2007), Parkinson’s disease (Jankovic et al., 2005; Le et al., 2008; Zhang et al., 2012), schizophrenia and bipolar disorder (Buervenich et al., 2000; Xing et al., 2006). This evidence concerns the gene NR4A2 and bipolar disorder.