The role of serotonin transporter and its functional gene polymorphism (5-HTTLPR, serotonin transporter linked polymorphic region) was investigated in sleep disturbances in various mental disorders, with conflicting findings.
Instead, based on current and previous findings, it is suggested that the S'/S' 5-HTTLPR genotype promotes the risk for stress-related sleep disturbances because of an increased susceptibility to the depressogenic consequences of stress.
Direct associations were identified between the dopamine receptor 3 (DRD3) BalI polymorphism and depression; the dopamine receptor 1 (DRD1) and dopamine transporter gene 3' VNTR polymorphisms and aberrant motor behavior; the DRD4 VNTR and sleep disturbances; and the SERT gene VNTR 5HTTLPR and apathy items.