Could Anxiety Increase the Risk of Developing Alzheimer’s Disease?

In patients with amnestic mild cognitive impairment, anxiety significantly increases the risk of conversion to Alzheimer’s disease, according to a recent study.

In order to explore the mechanisms behind the association between anxiety in patients with aMCI and Alzheimer’s disease risk,  researchers followed 376 participants with aMCI (ages 55 to 91 years) from the Alzheimer’s Disease Neuroimaging Initiative. Over the 3-year study period, changes in participants were monitored every 6 months.
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Using a Cox proportional-hazards model, researchers measured the association between anxiety severity (based on the Neuropsychiatric Inventory Questionnaire) and risk of developing Alzheimer’s disease. They also measured the relationship between anxiety symptoms and depression, and studied parts of the patients’ brains associated with Alzheimer’s development.

After controlling for depression and cognitive decline, researchers found that the risk of Alzheimer’s disease increased with severity of anxiety symptoms. They noted that despite severity of anxiety symptoms, most participants had low depression scores, suggesting that anxiety symptoms were independent of clinical depression.

“Anxiety symptoms in aMCI predict conversion to AD, over and beyond the effects of depression, memory loss, or atrophy within AD neuroimaging biomarkers,” the researchers concluded.

“These findings, together with the greater entorhinal cortical (EC) atrophy rate predicted by anxiety, are compatible with the hypothesis that anxiety is not a prodromal non-cognitive feature of AD, but may accelerate decline towards AD through direct or indirect effects on EC.”

The complete study is published in the October issue of Geriatric Psychiatry.

References:

Mah L, Binns MA, Steffens DC. Anxiety symptoms in amnestic mild cognitive impairment are associated with medial temporal atrophy and predict conversion to Alzheimer’s disease. Geriatric Psychiatry. 2014 November [epub ahead of print] doi: http://dx.doi.org/10.1016/j.jagp.2014.10.005.