Broadening the etiological discourse on Alzheimer's disease to include trauma and posttraumatic stress disorder as psychosocial risk factors.

Biomedical perspectives have long dominated research on the etiology and progression of Alzheimer's disease (AD); yet these approaches do not solely explain observed variations in individual AD trajectories. More robust biopsychosocial models regard the course of AD as a dialectical interplay of neuropathological and psychosocial influences. Drawing on this broader conceptualization, we conducted an extensive review of empirical and theoretical literature on the associations of trauma, posttraumatic stress disorder (PTSD) and AD to develop a working model that conceptualizes the role of psychosocial stressors and physiological mechanisms in the onset and course of AD. The proposed model suggests two pathways. In the first, previous life trauma acts as a risk factor for later-life onset of AD, either directly or mediated by PTSD or PTSD correlates. In the second, de novo AD experiential trauma is associated with accelerated cognitive decline, either directly or mediated through PTSD or PTSD correlates. Evidence synthesized in this paper indicates that previous life trauma and PTSD are strong candidates as psychosocial risk factors for AD and warrant further empirical scrutiny. Psychosocial and neurological-based intervention implications are discussed. A biopsychosocial approach has the capacity to enhance understanding of individual AD trajectories, moving the field toward 'person-centered' models of care.