Mental health disorders, such as stress and anxiety, continue to be the subject of much scientific research to assess their long-term impact on health – specifically on the risk of dementia.

This is with good reason: more than 55 million people worldwide have this condition, according to the World Health Organization, the most common form being Alzheimer’s disease.

While age, smoking, social isolation and a sedentary lifestyle are all known risk factors, researchers in Australia wanted to assess the impact of anxiety disorders on dementia risk.

Published in the Journal of the American Geriatrics Society, their research is based on data from 2,132 people aged 76 on average, with a median follow-up of 10 years. Conducted in three phases, each five years apart, the survey collected data on the participants’ health, and measured their anxiety at the start of the study and at the first follow-up.

The researchers defined “chronic anxiety” as anxiety present during the first two phases of the study; “new onset anxiety” as anxiety present only during the second phase; and “resolved anxiety” as anxiety present only during the first phase.

The findings report that the presence of chronic anxiety and new onset anxiety were respectively associated with 2.8 and 3.2 times higher risks of having dementia. And the risk is even higher in participants who experienced anxiety before the age of 70.

Meanwhile, cases of resolved anxiety were not associated with increased dementia risk – indeed, similar results were found in these participants as those who had no anxiety at all.

“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,” corresponding author Kay Khaing, of the University of Newcastle, concluded.

Symptoms of dementia include forgetting recent events, disorientation, loss of the sense of time, and difficulty in solving problems, following conversations or performing routine tasks.