Individuals who regularly suffer from stress-related disorders are at a higher risk of developing dementia, according to a new study on Thursday.

Professor Jang Sung-in’s research team from Yonsei University’s department of preventive medicine discovered a connection between stress and dementia by studying 8,906 patients diagnosed with stress-related disorders and 26,718 patients without such disorders over 11 years.

The findings were published in the latest issue of the international journal Scientific Reports.

The researchers categorized stress-related disorders into post-traumatic stress disorder, acute stress disorder and adjustment disorder, based on the severity of such disorders, to assess patients’ risk of developing dementia.

For patients diagnosed with PTSD, the risk of developing dementia was 1.78 times higher than for people without stress-related disorders. Patients diagnosed with acute stress disorder were found to have 1.2 times higher likelihood of developing dementia in the future, while those with adjustment disorder had 1.3 times higher likelihood.

PTSD is a psychiatric disorder that appears in individuals who have experienced or witnessed a traumatic event or a set of circumstances. Those suffering from PTSD have intense thoughts and feelings related to their experience that last long after the traumatic event has ended.

Since it is more likely for PTSD patients to develop dementia compared to patients diagnosed with other stress-related disorders, researchers suggested that severe, long-lasting stress-related disorders like PTSD have a correlation with dementia.

Among different types of dementia, Alzheimer’s disease was the most correlated to stress-related disorders, as researchers reported that the rate was 1.22 times higher for patients diagnosed with stress-related disorders to develop Alzheimer’s than those who had not been so diagnosed.

As expected, older patients with stress-related disorders are more likely to develop dementia, as researchers found that the rate was 31.6 times higher for patients over the age of 70 to develop dementia compared to patients in their 40s.

While patients with PTSD are at a higher risk of developing dementia compared to patients with milder types of stress-related disorders, researchers say it is still important for those without PTSD to keep the study results in mind.

“One must find ways to manage stress through a regular lifestyle routine or by exercising, enjoying their hobbies or having conversations with others,” said professor Jang. “Visiting a psychiatrist is advised if their stress levels cause mood swings or affect their quality of sleep.”