Logistic regression models in Table 4 showed that patients APOE ε4 allele was associated with the presences of HH (OR = 3.472, 95%CI: 1.082–11.144, p = 0.036) and depression (OR = 3.002, 95%CI: 1.079–8.353, p = 0.035) in the mild – moderate DLB patients after adjusted gender, age at visit, education, habits of smoking and alcohol consumption, heart disease, hypertension, diabetes mellitus, and stroke, while there was no associations between APOE ε4 allele and geriatric symptoms in mild-moderate PDD patients. The gene discussed is APOE; the disease is major depressive disorder.