October 18, 2023
Being chronically stressed may be bad for your cognitive health. A new study found that long-term stress and depression was tied to an increased risk for Alzheimer’s disease. Stress and depression also increased the risk of mild cognitive impairment, or MCI, a brain disorder marked by serious memory problems that often progresses to full-blown Alzheimer’s disease.
The findings provide further evidence of what many doctors, and patients, have long suspected: stress is bad for the brain. They also underscore the potential importance of stress relief in helping to mitigate the onset of Alzheimer’s, a consideration that may be particularly compelling as we continue to deal with the ongoing fallout of the COVID-19 pandemic and other stressful life and world events.
The study, by researchers at the Karolinska Institute in Sweden, looked at 46,345 men and women who were part of a large Swedish healthcare database. They ranged in age from 18 to 65. All had been given a diagnosis of depression or chronic stress, defined as being under persistent mental pressure with no opportunities for relief, for at least six months.
Over the next eight years, the researchers looked at how many of them had developed Alzheimer’s disease or MCI. They compared them to 1,316,203 of their peers of similar age who did not suffer from chronic stress or depression.
The researchers found that the risk of Alzheimer’s disease was more than twice as high in people with chronic stress or depression as it was in patients without either condition. In those with both chronic stress and depression, the chance of developing Alzheimer’s was up to four times higher.
The study also showed chronic stress and/or depression led to a similar risk of developing mild cognitive impairment.
The patient cohort was a generally younger population, under 65 at the start of the study, so the absolute risk of developing Alzheimer’s was “still very small,” said the study’s senior author, Axel C. Carlsson. “That said, the finding is important in that it enables us to improve preventative efforts and understand links with the other risk factors for dementia.”
The study showed only an association and could not prove cause and effect. But the study population was large, and other research has shown that mental health disorders can raise dementia risk. An earlier study from Sweden, for example, found that men and women with a diagnosis of depression were at increased risk of getting a dementia diagnosis, and the risk persisted for more than 20 years. Other large studies have found that people with post-traumatic stress disorder, including combat veterans with PTSD, likewise have an increased risk of developing dementia.
People who care for a loved one with Alzheimer’s disease may be particularly prone to chronic stress. Signs of unhealthy stress include feeling frustrated or irritable or easily triggered to anger; withdrawing from friends or social activities; lack of focus and concentration; feeling tired all the time; or feeling depressed or anxious.
Chronic stress can cause body-wide inflammation, and increasingly scientists think inflammation may play a role in Alzheimer’s disease and other diseases of aging. Studies have shown that chronic stress can also dampen the immune system, making us more vulnerable to colds and other infectious diseases.
How we cope with stress can also affect our lifestyle behaviors. People who are stressed may smoke more, sleep less, or be more likely to eat an unhealthy diet, all of which are recognized risk factors for Alzheimer’s disease.
Reducing stress is therefore critical for general health, in addition to brain health. There are many steps you can take to help reduce stress levels, studies show. Among them are the following.
Exercise. Regular physical activity can improve mood and allay stress, and it doesn’t take much. Taking the stairs, cleaning the house, going for a walk, or lifting light hand weights can all help you to manage stress. Find an activity that fits your schedule and that you enjoy, and establish a regular routine.
Head outdoors. Combining exercise with a trip outdoors or to a park can provide a double boost. Studies have shown that people who did activities outdoors generally enjoy them more and do them for longer. Those who exercised outdoors had lower levels of cortisol, a stress hormone, than those who did the same activities indoors.
Try relaxation exercises. Meditation, breathing exercises and other relaxation techniques have been shown to lower stress levels and boost the immune system. Meditation activates parts of the brain that help promote focus and calm, and after a four-month meditation program, participants showed lower levels of proteins tied to chronic inflammation. Keeping a journal or working on an art project is another way to promote calm and mental focus.
Connect with others. Reaching out to friends, neighbors and family members for extra help or for social activities is one of the most important things you can do to promote brain health. One researcher calculated that feeling lonely and isolated took a toll on health similar to smoking 15 cigarettes a day. Many studies show that giving support to others is a powerful way to ease stress and boost resilience.
Don’t forget the pets. Spending time with a pet can be an effective stress fighter. Dog owners get far more exercise than people who don’t own pets. Therapy dogs, cats, rabbits, even llamas are increasingly showing up in nursing homes, VA hospitals and long-term care facilities to help ease stress. After just 20 minutes with a therapy dog, studies show, levels of stress hormones drop considerably.
By ALZinfo.org, The Alzheimer’s Information Site. Reviewed by Eric Schmidt, Ph.D., Fisher Center for Alzheimer’s Research Foundation at The Rockefeller University.
Source: Johanna Wallensten, Gunnar Ljunggren, Anna Nager, et al: “Stress, depression, and risk of dementia – a cohort study in the total population between 18 and 65 years old in Region Stockholm.” Alzheimer’s Research & Therapy, October 2, 2023.
