Dwivedi Y. Involvement of brain-derived neurotrophic factor in late-life depression. Am J Geriatr Psychiatry. 2013;21(5):433-49. 

Brain-derived neurotrophic factor (BDNF) is one of the major neurotrophic factors, which plays an important role in the maintenance and survival of neurons, synaptic integrity, and synaptic plasticity. The present review shows that late-life depression is associated with disturbances in structural and neural plasticity as well as impairments in cognitive behavior and how BDNF gene could be critical in the development of late-life depression. Thus examining BDNF in these patients will have major clinical relevance in terms of pathophysiology and treatment.