Persistently engaging in negative thinking patterns may raise the risk of Alzheimer’s disease, finds a new UCL-led study.
In the study of people aged over 55, published in Alzheimer’s & Dementia, researchers found ‘repetitive negative thinking’ (RNT) is linked to subsequent cognitive decline as well as the deposition of harmful brain proteins linked to Alzheimer’s.
The researchers say RNT should now be further investigated as a potential risk factor for dementia, and psychological tools, such as mindfulness or meditation, should be studied to see if these could reduce dementia risk.
Lead author Dr. Natalie Marchant (UCL Psychiatry) said: “Depression and anxiety in mid-life and old age are already known to be risk factors for dementia.
Here, we found that certain thinking patterns implicated in depression and anxiety could be an underlying reason why people with those disorders are more likely to develop dementia.
We do not think the evidence suggests that short-term setbacks would increase one’s risk of dementia.
“We hope that our findings could be used to develop strategies to lower people’s risk of dementia by helping them to reduce their negative thinking patterns.”
For the Alzheimer’s Society-supported study, the research team from UCL, INSERM and McGill University studied 292 people over the age of 55 who were part of the PREVENT-AD cohort study, and a further 68 people from the IMAP+ cohort.
Over a period of two years, the study participants responded to questions about how they typically think about negative experiences, focusing on RNT patterns like rumination about the past and worry about the future. The participants also completed measures of depression and anxiety symptoms.
Their cognitive function was assessed, measuring memory, attention, spatial cognition, and language. Some (113) of the participants also underwent PET brain scans, measuring deposits of tau and amyloid, two proteins which cause the most common type of dementia, Alzheimer’s disease, when they build up in the brain.
The researchers found that people who exhibited higher RNT patterns experienced more cognitive decline over a four-year period, and declines in memory (which is among the earlier signs of Alzheimer’s disease), and they were more likely to have amyloid and tau deposits in their brain.
Depression and anxiety were associated with subsequent cognitive decline but not with either amyloid or tau deposition, suggesting that RNT could be the main reason why depression and anxiety contribute to Alzheimer’s disease risk.
“We propose that repetitive negative thinking may be a new risk factor for dementia as it could contribute to dementia in a unique way,” said Dr. Marchant.
The researchers suggest that RNT may contribute to Alzheimer’s risk via its impact on indicators of stress such as high blood pressure, as other studies have found that physiological stress can contribute to amyloid and tau deposition.
Co-author Dr. Gael Chételat (INSERM and Université de Caen-Normandie) commented: “Our thoughts can have a biological impact on our physical health, which might be positive or negative.
Mental training practices such as meditation might help promoting positive- while down-regulating negative-associated mental schemes.
“Looking after your mental health is important, and it should be a major public health priority, as it’s not only important for people’s health and well-being in the short term, but it could also impact your eventual risk of dementia.”
The researchers hope to find out if reducing RNT, possibly through mindfulness training or targeted talk therapy, could in turn reduce the risk of dementia. Dr. Marchant and Dr. Chételat and other European researchers are currently working on a large project to see if interventions such as meditation may help reduce dementia risk by supporting mental health in old age.
Fiona Carragher, Director of Research and Influencing at Alzheimer’s Society, said: “Understanding the factors that can increase the risk of dementia is vital in helping us improve our knowledge of this devastating condition and, where possible, developing prevention strategies.
The link shown between repeated negative thinking patterns and both cognitive decline and harmful deposits is interesting although we need further investigation to understand this better.
Most of the people in the study were already identified as being at higher risk of Alzheimer’s disease, so we would need to see if these results are echoed within the general population and if repeated negative thinking increases the risk of Alzheimer’s disease itself.
“During these unstable times, we are hearing from people every day on our Alzheimer’s Society Dementia Connect line who are feeling scared, confused, or struggling with their mental health.
So it’s important to point out that this isn’t saying a short-term period of negative thinking will cause Alzheimer’s disease. Mental health could be a vital cog in the prevention and treatment of dementia; more research will tell us to what extent.”
Alzheimer’s disease (AD) is a chronic intensifying incurable progressive disease leading to neurological deterioration manifested as impairment of memory and executive brain functioning affecting the physical ability like intellectual brilliance, common sense in patients.
The recent therapeutic approach in Alzheimer’s disease is only the symptomatic relief further emerging the need for therapeutic strategies to be targeted in managing the underlying silent killing progression of dreaded pathology.
Therefore, the current research direction is focused on identifying the molecular mechanisms leading to the evolution of the understanding of the neuropathology of Alzheimer’s disease.
The resultant saturation in the area of current targets (amyloid β, τ Protein, oxidative stress etc.) has led the scientific community to rethink of the mechanistic neurodegenerative pathways and reprogram the current research directions.
Although, the role of stress has been recognized for many years and contributing to the development of cognitive impairment, the area of stress has got the much-needed impetus recently and is being recognized as a modifiable menace for AD. Stress is an unavoidable human experience that can be resolved and normalized but chronic activation of stress pathways unsettle the physiological status.
Chronic stress mediated activation of neuroendocrine stimulation is generally linked to a high risk of developing AD. Chronic stress-driven physiological dysregulation and hypercortisolemia intermingle at the neuronal level and leads to functional (hypometabolism, excitotoxicity, inflammation) and anatomical remodeling of the brain architecture (senile plaques, τ tangles, hippocampal atrophy, retraction of spines) ending with severe cognitive deterioration.
The present review is an effort to collect the most pertinent evidence that support chronic stress as a realistic and modifiable therapeutic earmark for AD and to advocate glucocorticoid receptors as therapeutic interventions.
More information: Natalie L. Marchant et al, Repetitive negative thinking is associated with amyloid, tau, and cognitive decline, Alzheimer’s & Dementia (2020). DOI: 10.1002/alz.12116