Are you a negative thinker? Read this carefully. Researchers have found that repetitive negative thinking in later life may raise the risk of Alzheimer's disease.
The findings, published in the journal Alzheimer's & Dementia, revealed that persistently engaging in negative thinking patterns was linked to cognitive decline and greater deposits of two harmful proteins responsible for Alzheimer's disease.
"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," study lead author Natalie Marchant from the University College London in the UK.
In the study, the research team studied 292 people aged over 55 and found 'repetitive negative thinking' (RNT) is linked to subsequent cognitive decline as well as the deposition of harmful brain proteins linked to Alzheimer's.
Over a period of two years, the study participants responded to questions about how they typically think about negative experiences, focusing on the 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 the 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 findings showed 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).
Deposits in Brain
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 maybe a new risk factor for dementia as it could contribute to dementia in a unique way," Marchant said.
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.
They noted that 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.