[Depression and its relationship with mild cognitive impairment and Alzheimer disease: A review study]

The objective of the present study was to determine whether depression precedes Mild cognitive impairment (MCI) as a risk factor or as a predictor in Alzheimer's disease (AD). A systematic review of observational studies (cross-sectional and cohort or follow-up) was carried out using the PRISMA search algorithm, for clinical markers in MCI and AD, in the Science Direct, Springer, Scopus and Proquest databases. The study eligibility criteria included inclusion criteria: of types of documents, articles of primary studies, type of source scientific journals, published in the English language, from January 2010 to April 2020, in patients with MCI and AD and in the group of age included in people with a minimum age range of 45years. Exclusion criteria were: publications older than 10years because the aim of the article was to explore recent studies, secondary research studies, type of report document, languages other than English. 3385 articles were identified, of which 30 articles were finally selected. It was found that there is an association between depression and AD, but properly as a risk factor but not, as a predictor or clinical marker of the development of AD. The degree of association is greater when they present depressive symptoms and simultaneously report subjective memory complaints or the presence of MCI.