Article

Chronic Psychological Distress and Risk of Alzheimer’s Disease in Old Age

Rush Alzheimer's Disease Center, Rush University Medical Center, Chicago, Ill, USA.
Neuroepidemiology (Impact Factor: 2.56). 02/2006; 27(3):143-53. DOI: 10.1159/000095761
Source: PubMed

ABSTRACT

Clinical and pathological data from the Rush Memory and Aging Project were used to test the hypothesis that distress proneness is associated with increased risk of Alzheimer's disease (AD). More than 600 older persons without dementia completed a 6-item measure of neuroticism, a stable indicator of proneness to psychological distress. At annual intervals thereafter, they underwent uniform evaluations that included clinical classification of AD and administration of 18 cognitive tests. Those who died underwent brain autopsy from which composite measures of AD pathology were derived. During a mean of about 3 years of follow-up, 55 people were clinically diagnosed with AD. In analyses that controlled for age, sex, and education, persons with a high level of distress proneness (score = 24, 90th percentile) were 2.7 times more likely to develop AD than those not prone to distress (score = 6, 10th percentile). Adjustment for depressive symptomatology or frequency of cognitive, social, and physical activity did not substantially change this effect. Distress proneness was also associated with more rapid cognitive decline. Among 45 participants who died and underwent brain autopsy, distress proneness was unrelated to diverse measures of AD pathology and was inversely related to cognition after controlling for AD pathology. The results support the hypothesis that distress proneness is associated with increased risk of dementia and suggest that neurobiologic mechanisms other than AD pathology may underlie the association.

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    • "AD is predominantly a sporadic disease, with less than 2% of cases linked to specific genetic mutations. An extensive literature implicates chronic stress in the development of sporadic AD2122232425which supports a body of epidemiological work demonstrating that individuals prone to experience psychological distress or anxiety have accelerated rates of cognitive decline and are three times more likely to be diagnosed with AD26272829. Furthermore, stress exposure in humans affects learning, memory, hippocampal function and morphology[26,27]. "
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    ABSTRACT: Stress exposure or increased levels of corticotropin-releasing factor (CRF) induce hippocampal tau phosphorylation (tau-P) in rodent models, a process that is dependent on the type-1 CRF receptor (CRFR1). Although these preclinical studies on stress-induced tau-P provide mechanistic insight for epidemiological work that identifies stress as a risk factor for Alzheimer's disease (AD), the actual impact of stress-induced tau-P on neuronal function remains unclear. To determine the functional consequences of stress-induced tau-P, we developed a novel mouse neuronal cell culture system to explore the impact of acute (0.5hr) and chronic (2hr) CRF treatment on tau-P and integral cell processes such as axon transport. Consistent with in vivo reports, we found that chronic CRF treatment increased tau-P levels and caused globular accumulations of phosphorylated tau in dendritic and axonal processes. Furthermore, while both acute and chronic CRF treatment led to significant reduction in CREB activation and axon transport of brain-derived neurotrophic factor (BDNF), this was not the case with mitochondrial transport. Acute CRF treatment caused increased mitochondrial velocity and distance traveled in neurons, while chronic CRF treatment modestly decreased mitochondrial velocity and greatly increased distance traveled. These results suggest that transport of cellular energetics may take priority over growth factors during stress. Tau-P was required for these changes, as co-treatment of CRF with a GSK kinase inhibitor prevented CRF-induced tau-P and all axon transport changes. Collectively, our results provide mechanistic insight into the consequences of stress peptide-induced tau-P and provide an explanation for how chronic stress via CRF may lead to neuronal vulnerability in AD.
    Full-text · Article · Jan 2016 · PLoS ONE
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    • "According to leading stress researcher Robert Sapolsky Ph.D., a stressor can be defined physiologically as any perturbation from the outside world that disrupts homeostasis [14]. Beyond the physical, stress can also be psychological or emotional and the potency and pathogenicity of psychological stress cannot be ignored, as it may increase the risk of developing AD [15]. Modern stress research is considered to have begun in the last century with the work of Walter B. Cannon [16], and later recognized as the first stage of Selye's general adaptation syndrome [17]. "
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    ABSTRACT: Although meditation is believed to be over five thousand years old, scientific research on it is in its infancy. Mitigating the extensive negative biochemical effects of stress is a superficially discussed target of Alzheimer's disease (AD) prevention, yet may be critically important. This paper reviews lifestyle and stress as possible factors contributing to AD and meditation's effects on cognition and well-being for reduction of neurodegeneration and prevention of AD. This review highlights Kirtan Kriya (KK), an easy, cost effective meditation technique requiring only 12 minutes a day, which has been successfully employed to improve memory in studies of people with subjective cognitive decline, mild cognitive impairment, and highly stressed caregivers, all of whom are at increased risk for subsequent development of AD. KK has also been shown to improve sleep, decrease depression, reduce anxiety, down regulate inflammatory genes, upregulate immune system genes, improve insulin and glucose regulatory genes, and increase telomerase by 43%; the largest ever recorded. KK also improves psycho-spiritual well-being or spiritual fitness, important for maintenance of cognitive function and prevention of AD. KK is easy to learn and practice by aging individuals. It is the premise of this review that meditation in general, and KK specifically, along with other modalities such as dietary modification, physical exercise, mental stimulation, and socialization, may be beneficial as part of an AD prevention program.
    Full-text · Article · Oct 2015 · Journal of Alzheimer's disease: JAD
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    • "The link between distress and the diagnosis of dementia remained after controlling for depression, levels of social and physical activity, and recency of cognitive symptoms. Echoing their prior work, the authors concluded that psychological distress is associated with cognitive decline, but not specifically with AD [6]. Peavy and colleagues performed a 3-year longitudinal study on 52 individuals, who were either cognitively intact or evidencing signs of mild cognitive impairment (MCI). "
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    ABSTRACT: The physiological consequences of acute and chronic stress on a range of organ systems have been well documented after the pioneering work of Hans Selye more than 70 years ago. More recently, an association between exposure to stressful life events and the development of later-life cognitive dysfunction has been proposed. Several plausible neurohormonal pathways and genetic mechanisms exist to support such an association. However, many logistical and methodological barriers must be overcome before a defined causal linkage can be firmly established. Here the authors review recent studies of the long-term cognitive consequences of exposures to cumulative ordinary life stressors as well as extraordinary traumatic events leading to posttraumatic stress disorder. Suggestive effects have been demonstrated for the role of life stress in general, and posttraumatic stress disorder in particular, on a range of negative cognitive outcomes, including worse than normal changes with aging, Alzheimer's disease, and vascular dementia. However, given the magnitude of the issue, well-controlled studies are relatively few in number, and the effects they have revealed are modest in size. Moreover, the effects have typically only been demonstrated on a selective subset of measures and outcomes. Potentially confounding factors abound and complicate causal relationships despite efforts to contain them. More well-controlled, carefully executed longitudinal studies are needed to confirm the apparent association between stress and dementia, clarify causal relationships, develop reliable antemortem markers, and delineate distinct patterns of risk in subsets of individuals.
    Full-text · Article · Jun 2014 · Alzheimer's and Dementia
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