Association between cognitive impairment and presence of the apolipoprotein E epsilon4 allele in elderly patients with major depressive disorder

This knowledge has generated interest in the in fl uence of ApoE variants on cognition in different psychiatric conditions. Thus, we have performed a study in order to investigate the role of the ApoE4 allele in the cognition of patients with major depressive disorder according to the criteria established by the Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV).Thirteen elderly patients older than 60 years [nine women (69.2%) and four men (30.8%)], all of them with a diagnosis of major depressive disorder according to DSM-IV criteria, were included in the study. Blood samples of all subjects were collected for genetic investigation. Patients were divided into two groups, according to the presence or absence of the ApoE4 allele (ApoE4 and non-ApoE4 groups). Genotyping was performed by two investigators according to Hixson & Vernier,