A new study shows that people with mild cognitive impairment (MCI) and high levels of stress have a greater risk of developing Alzheimer’s disease than their peers who aren’t stressed out.
According to an article in the American Journal of Geriatric Psychiatry, MCI patients who experience anxiety symptoms tend to undergo a speedier decline in cognitive function, whether or not they have depression, which is also a risk factor for Alzheimer’s.
A research team at Baycrest Health Sciences' Rotman Research Institute in Canada found that the risk of Alzheimer’s increased among those with mild, moderate, or severe anxiety by 33 percent, 78 percent, and 135 percent, respectively. They studied 376 adults between the ages of 55 and 91 over a three-year period, keeping an eye on cognitive changes every six months.
Study participants were diagnosed with MCI but had low scores on a rating scale that measures depression. This means that their anxiety symptoms were not caused by clinical depression. Dr. Linda Mah, a clinical scientist at the Rotman Research Institute and an assistant professor of psychiatry at the University of Toronto, led the research. She said it clearly shows that MCI patients with anxiety are at a higher risk for developing Alzheimer’s, and that the more severe the anxiety, the greater the risk of progressing to Alzheimer’s.
“We cannot tell from this study whether interventions to reduce anxiety will also reduce risk of Alzheimer’s disease … we need future studies to answer this question,” Mah said. Doctors do know that lifestyle interventions such as exercise and more social interaction can reduce anxiety and seem to slow cognitive decline.
“I am hoping that people with MCI who are experiencing stress or anxiety but are not able to find the time, or are putting off, engaging in those lifestyle interventions like exercise will be more strongly motivated to do so as a result of our study's findings,” Mah added.
Treating Anxiety to Thwart Alzheimer’s
Experts believe that late-life depression poses a significant risk in terms of developing Alzheimer's. Doctors routinely screen older patients for depression, but not anxiety.
“Our findings suggest that clinicians should routinely screen for anxiety in people who have memory problems because anxiety signals that these people are at greater risk for developing Alzheimer's,” Mah said.
Mah said there is no evidence to show that anti-anxiety drugs can manage anxiety in those with MCI or decrease their risk of developing Alzheimer’s.
“We think that, at the very least, behavioral stress management programs could be recommended,” Mah said. “In particular, there has been research on the use of mindfulness-based stress reduction in treating anxiety and other psychiatric symptoms in Alzheimer’s — and this is showing promise.”
How Anxiety Affects the Brain
Can anxiety actually impair our brain function?
The researchers also found that MCI patients with anxiety had greater rates of atrophy, or stunting, in their brains’ medial temporal lobe — a part of the brain that creates memories and is often compromised in Alzheimer’s patients. Mah said some animal studies have demonstrated that anxiety and stress can also damage the hippocampus, which is another part of the brain involved in forming memories.
She said that anxiety symptoms reported at any point in the study predicted greater damage to brain regions that are implicated or abnormal in Alzheimer's.
Having MCI doesn’t mean that a person will automatically develop Alzheimer’s; some people see improvement in their cognitive power. The study shows, however, that anxiety can be a “predictive factor” to forecast whether an MCI patient is likely to develop the disease.
According to previous research, Mah said, MCI patients with anxiety have abnormal levels of plasma amyloid protein and T-tau proteins in their cerebrospinal fluid, which is an indicator of Alzheimer's. Chronic stress and depression have also been tied to a smaller hippocampus and a higher risk of dementia.