Cognition and Bipolar Disorder in Older Adults (Including Question of “Neuroprogression”)

Abstract

The rise in life expectancy has in turn led to an increase in the proportion of older adults with bipolar disorder (OABD), with the consequent need to improve understanding of the clinical features of this population. However, only in the last decade has the neurocognitive profile of OABD begun to be described. Cross-sectional studies in OABD showed impairments in verbal memory, attention, and executive functions with medium to large effect sizes compared to healthy controls, which closely resemble the findings of younger patients. The first longitudinal studies in OABD tend to find that cognitive deficits are static rather than progressive. Therefore, both cross-sectional and longitudinal studies do not appear to support the notion of progressive cognitive impairment over the course of the disease, which is proposed as the hypothesis for neuroprogression and staging models for BD. On the other hand, preliminary evidence has suggested a possible association between BD and an increased risk of developing dementia, although the underlying causes are still matters of speculation. Some cases of late-onset BD may represent early stages of neurodegenerative or cerebrovascular diseases and contribute in part to this association. In addition, there are multiple factors that can affect cognitive function in OABD such as the exposure to psychotropic drugs and different medical and psychiatric comorbidities. The clinical and theoretical implications of these topics are discussed throughout this chapter.