If the diagnosis of depression is made but the presence of supportive DLB’s features strongly suggests the possibility of a prodromal state of DLB, follow-up may be required, including dopamine transporter scintigraphy, MIBG myocardial scintigraphy, and polysomnography, which are index biomarkers of DLB, as well as confirmation of response to treatment [100]. This evidence concerns the gene SLC6A3 and Lewy body dementia.