There is no doubt that dementia patients suffer from anxiety. Fear and confusion will do that to a person.

But does the relationship go the other way? Does anxiety increase the risk of developing dementia? Could it be a cause?

The link between the two is well established. But the nature of the relationship between dementia and anxiety remains somewhat controversial.

A 2020 meta-analysis of eight studies, involving 29,608 participants, made a curious conclusion: Anxiety was significantly associated with an increased risk of all-cause dementia.

The treatment or prevention of anxiety “might help to reduce dementia incidence rates”.

But more research was needed “to clarify whether anxiety is a cause of dementia rather than a prodrome”.

A prodome is an early symptom. Of course, it may be both a cause and a symptom.

The latest

A new study out of Newcastle University finds that both chronic and new-onset anxiety is associated with an increased risk of dementia.

However, where anxiety had resolved, there was no association with dementia risk.

Presumably, this resolution occurred before the anxiety had caused damage to the brain via stress.

The study included 2132 participants, with an average age of 76 years, from the Hunter Community Study, who were followed for an average of 10 years.

The presence of chronic anxiety and new onset anxiety were associated with 2.8- and 3.2-times higher risks of having dementia, respectively.

Even higher risks were seen in adults with anxiety before the age of 70 years. This is presumably because they suffered with anxiety for longer periods.

People whose anxiety resolved “did not have a higher dementia risk than people without current or past anxiety”.

“While this sort of question cannot be subject to a randomized controlled trial, this prospective cohort study used causal inference methods to explore the role of anxiety in promoting the development of dementia,” said corresponding author Kay Khaing.

“The findings suggest that anxiety may be a new risk factor to target in the prevention of dementia and also indicate that treating anxiety may reduce this risk.”

The Hunter Community Study is a longitudinal cohort study of men and women aged 55 to 85 years who reside in Newcastle, NSW.

How anxiety may cause dementia

A series of studies found that chronic anxiety and associated stress damages and shrinks the brain. We’re not talking here about the every-day ordinary anxiety we all cope with from time to time, but rather crippling anxiety that impacts daily function.

Studies have found a strong association between anxiety, chronic stress, and impaired memory function, and an increased risk of Alzheimer’s disease. One study, with a 38 year follow-up, found an increased risk of Alzheimer’s disease.

A 2010 study found significantly reduced hippocampal size in participants who suffered from anxiety. The hippocampus is a complex brain structure with a major role in learning and memory.

It is a plastic and vulnerable structure that gets damaged by a variety of stimuli. Studies have shown that it also gets affected in a variety of neurological and psychiatric disorders.

A 2016 study found that pathological anxiety and chronic stress were “associated with structural degeneration and impaired functioning of the hippocampus and the prefrontal cortex”.

This was thought to account “for the increased risk of developing neuropsychiatric disorders, including depression and dementia”.

Anxiety is known to have a negative impact on the working memory.

A 2019 meta-analysis involving more than 500 participants found that increased anxiety was associated with impaired measures of verbal and visuospatial working memory.

A strong working memory is vital for everyday functioning. It facilitates planning, comprehension, reasoning, and problem-solving. You use your working memory when you do mental arithmetic, follow instructions, or rehearse.

Further, a 2017 study found that stress and anxiety impaired decision-making and sustained attention.