Strong Link Found Between Anxiety, Cognitive Impairment

A growing body of research reveals that the prevalence of late-life anxiety coexisting with cognitive impairment is more common than may have been suspected. And it appears that a symbiotic relationship exists between the two.

These are the conclusions drawn by Stanford University School of Medicine researchers Sherry Beaudreau, Ph.D., and Ruth O'Hara, Ph.D., from their literature review on the subject. Their study was published in the October American Journal of Geriatric Psychiatry.

“We conducted an extensive literature search using PubMed, and [we] also included relevant articles that were listed in the references of the articles we found,” Beaudreau, the study's lead author, told Psychiatric News. “Preliminary evidence suggests that the impact of both [late-age anxiety and cognitive impairment] is greater than for either one alone. However, much work needs to be done in this area.”

Beaudreau is a clinical assistant professor with the Department of Psychiatry and Behavioral Sciences at Stanford University School of Medicine. O'Hara is an associate professor in the same department. Both are affiliated with the Veterans Affairs Palo Alto Health Care System.

The two mined the research for evidence that might show whether there is a higher prevalence of anxiety in cognitively impaired individuals in their later years, whether there is a causal relationship between heightened levels of anxiety in this population and poorer cognitive functioning, and whether such anxiety can predict future cognitive decline in this age group.

These are important questions, they said, because if there is a cause-and-effect relationship between the two conditions it may likely explain the “poorer treatment prognosis for both.” They said that this, in turn, could be the basis for calling for more targeted research to better understand the preclinical development of dementia and for determining the best ways to treat late-life anxiety.

Which Gets Treated First?

“A significant clinical concern is which problem to treat first when both anxiety and cognitive impairment are present,” Beaudreau and O'Hara wrote. “Augmenting or combining standard treatments [pharmacology for cognitive problems and psychotherapy for anxiety] is an important venue for researchers and clinicians to consider.”

The literature makes clear that “anxiety disorders are the most common late-life psychiatric diagnoses, with an estimated lifetime prevalence of 15.3 percent in older adults, surpassing population estimates for mood disorders and severe cognitive impairment,” the researchers found. So although late-life depression, especially related to loss, is an important issue and has been researched more, “the reciprocal relationship between late-life anxiety and cognition merits attention,” which is why they embarked on this study.

Because generalized anxiety disorder (GAD) is the primary type of anxiety discussed in the literature, GAD became the exclusive focus of the review. It has a lifetime prevalence of 10.2 percent in older individuals, according to a longitudinal study in the Netherlands of 3,056 adults aged 55 to 85 reported in 1998 by Aartjan Beekman, M.D., Ph.D., and colleagues in the International Journal of Geriatric Psychiatry. Symptoms include an overly excessive apprehension of or preoccupation over the daily events and activities of life.

As many as 30 percent of adults experience mild cognitive impairment, the authors determined via their literature review.

Overall, the research reviewed by Beaudreau and O'Hara, while not conclusive, revealed more than a casual relationship between GAD and mild cognitive impairment.

“Although the influence of GAD or worry symptoms on cognitive functioning is not well delineated in the literature, there is some evidence for reduced cognitive performance, in particular reduced episodic memory and executive function in young and middle-aged adults with anxiety disorder,” they noted.

Brain Changes May Be Responsible

Some speculate that structural changes in the brain may be implicated in late-life anxiety and cognitive changes. “One of the few such studies... implicates functional impairments in the dorsolateral region of the prefrontal cortex, an area strongly influencing diverse cognitive processes, particularly executive functions,” reported Sanjay Mathew, M.D., and colleagues in an imaging study reported in the June 2004 American Journal of Psychiatry.

Meanwhile, a number of cross-sectional studies have found that older adults who exhibited cognitive deficits had more symptoms of anxiety than did control subjects and that there was a relationship between poorer cognitive functioning in older adults and heightened anxiety. Chief among these studies are “Prevalence of Neuropsychiatry Symptoms in Dementia and Mild Cognitive Impairment,” by Constantine Lyketsos, M.D., and colleauges in the September 2002 JAMA, and “De Nova Genesis of Neuropsychiatric Symptoms in Mild Cognitive Impairment” by Yonas Geda, M.D., and colleagues reported in the April 2004 International Psychogeriatrics.

Beaudreau and O'Hara also identified a few longitudinal studies that determined that the level of an elderly individual's anxiety could be “a predictor of future cognitive decline.” Chief among these was one by Gary Sinoff and Perla Werner in the September 2003 International Journal of Geriatric Psychiatry.

The clinically instructive lesson is clear: “treatment focusing on only one disorder is not likely to be effective,” Beekman wrote in a Journal of Geriatric Psychiatry editorial that critiqued Beaudreau and O'Hara's review. Then again, “as anxiety is a treatable problem, this may represent an avenue to prevent or slow down cognitive decline,” Beekman suggested. He is with the Department of Psychiatry at VU University Medical Centre and BuitenAmstel Geestgronden Mental Health Institute in Amsterdam, the Netherlands.

An abstract of “Late-Life Anxiety and Cognitive Impairment: A Review” is posted at<http://ajgponline.org/cgi/content/abstract/16/10/790>.▪