Researchers have identified a new factor that may increase the risk for developing dementia: anxiety. People who experienced high levels of anxiety at any time in their lives were 48% more likely to develop dementia as they aged compared to people who did not experience anxiety.

The new study, published in Alzheimer’s and Dementia, evaluated nearly three decades of data from a Swedish study of twins. By comparing the lives and medical histories of more than 1,000 fraternal and identical twins, the authors were able to uncover a link between anxiety and dementia. The study participants completed tests, questionnaires, and screenings every three years throughout the study.

Overall, anxiety symptoms were significantly associated with an increased risk of dementia. The association between anxiety and dementia was stronger among fraternal twins than among identical twins, which calls to question genetic components of both anxiety and dementia.

Many studies have reported connections between dementia and other psychological conditions, including depression and neuroticism. The link observed in the current study was independent of other psychological variables. Anxiety, in general, is not as well studied as other mental health conditions – especially in older adults – because it can be viewed as a personality trait rather than a psychological condition.

In the current twin study, the authors note that the participants who had anxiety and later developed dementia experienced more than usual symptoms of anxiety; these participants were fidgety and chronically stressed. A limitation of the findings is that the levels of anxiety were self-reported by the twins, and not all signs or symptoms of anxiety may have met the diagnostic criteria for an anxiety disorder.

Why might anxiety increase dementia?

Anxiety may increase the risk of dementia by stressing the circuits in the brain that are regulated by the amygdala, the hippocampus, and the prefrontal cortex. Chronic stress can lead to structural degeneration and impaired functioning of the brain, which, over time, can lead to dementia, among other conditions. Current investigations hope to determine if pharmacological or non-pharmacological interventions can reverse these stress-induced brain changes. It was unclear in the twin study if treatment for anxiety mitigated the risk of developing dementia.

Like most mental health conditions and diseases, dementia is likely caused by a combination of genetic and environmental factors. We cannot yet predict who will get dementia and who will not, nor can we treat dementia effectively. But, the more links and associations we identify about risk factors and causes of this devastating condition, the brighter the future of psychological health care looks for older adults.

References

Leuner B, & Shors TJ (2013). Stress, anxiety, and dendritic spines: what are the connections? Neuroscience, 251, 108-19 PMID: 22522470

Mah L, Szabuniewicz C, & Fiocco AJ (2016). Can anxiety damage the brain? Current opinion in psychiatry, 29 (1), 56-63 PMID: 26651008

Petkus AJ, Reynolds CA, Wetherell JL, Kremen WS, Pedersen NL, & Gatz M (2015). Anxiety is associated with increased risk of dementia in older Swedish twins. Alzheimer’s & dementia : the journal of the Alzheimer’s Association PMID: 26549599

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