Flavanol Augmentation for Antidepressant Non-Responsive Late Life Depression

The goal of this proposal is to conduct the first pilot study of whether consuming a diet high in flavanols will augment the cognitive and mood benefits of antidepressant medication in older adults with Late Life Depression (LLD). LLD affects 3% of community-dwelling adults over 60 years old, and 15% of older adults living in the community have clinically significant depressive symptoms. Diagnosis with LLD increases an older adult's risk of disability by 67-73% over 6 year follow up, causes twice the functional impairment compared to those without LLD, and is associated with high rates of completed suicide in individuals over 65. Currently available treatments for LLD (i.e., antidepressant medication) are limited in efficacy, leading to high rates of recurrence and frequent development of chronicity. Cognitive impairment, which is commonly associated with LLD, predicts poor acute response to antidepressants, leads to higher relapse rates during the continuation phase of treatment, and is associated with the development of adverse age-related health outcomes, including increased risk of dementia, dependence in activities of daily living (ADL), and driving cessation. Novel treatments addressing LLD's underlying neurobiology are critically needed, particularly therapies that may also have beneficial effects on the cognitive components of LLD. The most extensively studied brain region to be implicated in both the depressive and cognitive aspects of LLD has been the hippocampus. Decreased hippocampal volumes are found in depressed patients compared to controls, and this finding appears to be particularly pronounced in individuals with recurrent depressive illness. Among the subregions comprising the hippocampus, evidence suggests that it is decreased neurogenesis within the dentate gyrus (DG) specifically that may contribute to the development of depression, and it appears that part of the mechanism of action of antidepressants is to enhance neurogenesis in the DG. As the DG is also a critical contributor to the cognitive functions of the hippocampus, it stands out as a highly significant brain region that may be involved with both the mood and cognitive components of LLD.