Depression is a common neuropsychiatric manifestation among Alzheimer’s disease (AD)
patients. It may compromise everyday activities and lead to a faster cognitive decline as well as worse
quality of life. The identification of promising biomarkers may therefore help to timely initiate and
improve the treatment of preclinical and clinical states of AD, and to improve the long-term functional
outcome. In this narrative review, we report studies that investigated biomarkers for AD-related depression.
Genetic findings state AD-related depression as a rather complex, multifactorial trait with
relevant environmental and inherited contributors. However, one specific set of genes, the brain derived
neurotrophic factor (BDNF), specifically the Val66Met polymorphism, may play a crucial role in
AD-related depression. Regarding neuroimaging markers, the most promising findings reveal structural
impairments in the cortico-subcortical networks that are related to affect regulation and reward /
aversion control. Functional imaging studies reveal abnormalities in predominantly frontal and temporal
regions. Furthermore, CSF based biomarkers are seen as potentially promising for the diagnostic
process showing abnormalities in metabolic pathways that contribute to AD-related depression. However,
there is a need for standardization of methodological issues and for replication of current evidence
with larger cohorts and prospective studies.
Factors related to perceived quality of life in patients with Alzheimer's disease: the patient's perception compared with that of caregivers
