Caregiving over time: The impact of the behavioral and psychological symptoms of dementia on caregiver depression

This dissertation was motivated by the growth in the number of elderly with dementia in the United States and worldwide, and the consequent need to assist caregivers who face the chronic stress and consequent negative outcomes of caring for dementia patients for increasingly longer periods of time. While behavioral and psychological symptoms of dementia (BPSD) are routinely cited as important predictors of negative caregiving outcomes, they consist of a wide variety of patient behaviors (e.g., depression, physical aggression and paranoid delusions). This dissertation aimed to further elucidate the BPSD-caregiver relationship by determining if and why individual components of BPSD impacted caregiver depression, how these relationships change over time, and how the timing of behaviors across the disease course affect the caregiver. First, via a systematic literature review we found that despite the significant amount of research conducted examining BPSD and caregiving, the literature focused on the aggregate effect of symptoms rather than on the effect of individual symptoms. Existing studies categorized BPSD based on how they clinically manifest in the patient, rather than from the perspective of how they may differentially impact the caregiver. Second, we tested the differential impact of four symptom clusters derived based on their likely impact on the caregiver (accusatory/aggressive symptoms, non-threatening psychotic symptoms, depressive symptoms, and difficult behaviors) on caregiver depression. All clusters exerted similar effect sizes on caregiver depression, with patient depressive symptoms exerting the strongest and most consistently stable relationship with caregiver depression. The patient depression-caregiver depression relationship was mediated by both perceived burden to caregivers and impact of symptoms on the patient. Finally, we did not find evidence that the presence of individual BPSD early in the disease course impacted subsequent caregiver depressive symptoms. When examining change patterns over time, we found that most caregivers had stable trajectories of depressive symptoms, with a smaller subset showing more evidence for wear-and-tear over time. Given that there may be a differential effect of individual symptoms on caregivers, research in this field should continue to study the effects of individual BPSD symptoms rather than the cumulative effects of a range of behaviors and should also consider how symptoms may negatively impact caregivers by evoking empathy in addition to increasing burden for the patient. Future work should continue to utilize a longitudinal perspective on caregiving to better characterize the relationship between individual BPSD and caregiver outcomes and to understand varied outcome trajectories. The continued focus on understanding how, why and when BPSD are most detrimental to caregivers can help target and improve patient treatment and caregiver intervention efforts.