Moreover, interactions between several genes (the glucocorticoid receptor (GR)) (Bakker et al., 2017), FKBP5 (Matosin, Halldorsdottir & Binder, 2018; Normann & Buttenschøn, 2020), 5-hydroxytryptamine transporter (5-HTTLPR) (Huang et al., 2014) and dopamine D2 receptor (DRD2) (Jiang et al., 2020) and exposure to job stress have repeatedly been found to play a role in the onset of sleep disturbances. This evidence concerns the gene DRD2 and sleep disorder.