A Mixed Methods Study of Behavioral Symptoms of Dementia among Older Veterans with and without Posttraumatic Stress Disorder in Residential Long-Term Care Settings

Behavioral symptoms of dementia cause considerable distress for persons with dementia and their caregivers and are related to adverse outcomes that have significant social and economic impact. Thus, behavioral symptoms represent one of the most challenging aspects of dementia care. Over the past three decades, research on behavioral symptoms of dementia has laid the foundation for development of non-pharmacological interventions by identifying underlying mechanisms of symptom development. However, the research has largely overlooked how the needs of military veterans may influence development and treatment of behavioral symptoms of dementia, including those needs associated with co-occurring dementia and posttraumatic stress disorder (PTSD). This dissertation aimed to develop knowledge related to behavioral symptoms of dementia among older veterans with and without PTSD by synthesizing current understanding of neurocognitive and psychiatric comorbidities of PTSD among veterans as well as explicating relationships among background factors, proximal factors, and behavioral symptoms of dementia among veterans living in residential care using the need-driven, dementia-compromised behavior (NDB) model.

This dissertation includes a systematic review in Chapter 2 that synthesized the patterns of neurocognitive and psychiatric comorbidities of PTSD in older veterans and revealed a substantial gap in the literature with regards to understanding manifestations and treatment of behavioral symptoms of dementia among older veterans with co-occurring dementia and PTSD. The primary study of this dissertation that encompasses Chapters 3 and 4 utilized an exploratory sequential mixed methods design using secondary data derived from the evaluation dataset of the STAR-VA training program. In Chapter 3, a qualitative study, as the first phase of the mixed methods study, analyzed text data that captured the interdisciplinary care team’s observation of behavioral symptoms of dementia and their circumstances for the subsample of 33 veterans from the STAR-VA dataset. This qualitative study described how behavioral symptoms of dementia are manifested among veterans with and without PTSD in the context of personal, interpersonal/social, and environmental factors that trigger the symptoms. Findings demonstrated that behavioral symptoms of dementia are heterogeneous, with distinct clusters of triggers that are multi-level, thereby warranting an interdisciplinary, multi-level approach to developing person-centered interventions. In addition, findings from this qualitative study informed the development of the second phase of the sequential mixed methods study in Chapter 4 that aimed to test hypothesized pathways between background factors, interpersonal triggers (proximal factors), and behavioral symptoms of rejection of care and aggression and to explore the moderating effect of PTSD on the hypothesized pathways. The mixed methods approach integrated quantitative data measured by standardized scales and text data for 315 veterans derived from the STAR-VA dataset. After converting text data into categorical variables, structural equation modeling (SEM) was performed to compare the patterns of relationships among background factors, interpersonal triggers, and behavioral symptoms of rejection of care and aggression between veterans with and without PTSD. The direct effect of interpersonal triggers and the indirect effect of background factors through interpersonal triggers on rejection of care and aggression emphasizes the importance of developing and implementing psychosocial interventions that improve interpersonal relationships. The multi-group SEM revealed that the full model was not moderated by PTSD. However, the differential direct and indirect effect of background factors and interpersonal triggers as a proximal factor on the behavioral outcomes between veterans with and without PTSD suggest potential different mechanisms of behavioral outcomes between veterans depending upon whether or not PTSD is present. Evidence for the PTSD-moderated mediating effect of interpersonal triggers on the relationship between depression and rejection of care was demonstrated, suggesting the need to develop targeted interventions for veterans with dementia and PTSD who have greater depressive symptoms.

The new knowledge generated from this dissertation helps to clarify complex patterns of associations among background factors such as PTSD and proximal factors and behavioral symptoms of dementia consistent with the NDB model, strengthening the foundation for development of novel approaches to designing and implementing person-centered care for veterans with co-occurring dementia and PTSD.