Subjective memory complaints associated with depression and cognitive impairment in the elderly: A systematic review

The aging process can be accompanied by a slight decline in cognitive functioning, and subjective memory complaints (SMC) appear to be common in the elderly population. OBJECTIVE: To determine whether SMC is associated with cognitive loss or depression and can predict dementia. METHODS: A systematic review of the literature was conducted. Articles were selected on the following databases, LILACS, SCOPUS, SCiELO, PubMed and Web of Science from August to October 2013. Article selection was based on inclusion and exclusion criteria. Studies published between 2010 and 2013, written in English, Spanish or Portuguese, involving populations 65 years or older, were included. Reviews were excluded. RESULTS: After the selection, a summary of the 20 articles retrieved was carried out. Of the total articles retrieved, fifteen were cross-sectional studies and five were longitudinal studies. Most of the cross-sectional studies associated SMC with depression, objective cognitive impairment and anxiety. The emergence of dementia in people with SMC was evidenced in longitudinal studies. Albeit less frequently, SMC were also associated with reduced quality of life, impairment in Activities of Daily Living (ADL), emergence of neuropsychiatric symptoms, lower hippocampal volume, amygdala volume reduction, increased activation of the left temporal, bilateral thalamus, caudate and posterior cingulate, and with the occurrence of ApoE ε4. CONCLUSION: SMC may be associated with changes in mood and/or cognition, and its occurrence appears to increase the likelihood of dementia. In order to further our understanding of the topic, future studies should consider the recruitment of representative samples with control groups and longitudinal designs.