Constant negative thoughts could increase dementia risk, say scientists

Researchers at the University College London (UCL) have found repetitive negative thinking (RNT) is linked to the deposit of harmful proteins in the brain associated with Alzheimer's disease, the most common type of dementia.

The team said these risks are associated with long periods of RNT rather than short-term negative thinking, with lead author Dr Natalie Marchant, of UCL Psychiatry, adding: "We do not think the evidence suggests that short-term setbacks would increase one's risk of dementia."

Based on the findings published in the journal Alzheimer's & Dementia, the scientists are calling for further research into RNT as a potential risk factor for dementia.

But Fiona Carragher, director of policy and influencing at Alzheimer's Society, said that while the link between RNT patterns and both cognitive decline and harmful brain deposits is interesting, further investigation is needed to understand more about this connection.

She added: "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."

In the study supported by the Alzheimer's Society, the researchers looked at 292 people over the age of 55 over two years.

The participants completed questionnaires about how they typically think about negative experiences.

Measures of depression and anxiety symptoms were also taken into account while cognitive functions were assessed using measures such as memory and attention span, as well as spatial cognition and language.

Brain scans were used to measure the deposits of two types of brain proteins - tau and amyloid - associated with Alzheimer's disease, in 113 study participants.