Can people with depression and anxiety develop Alzheimer’s at a younger age? Study says it may be possible
Several factors can increase the risk of developing Alzheimer’s, the most common cause of dementia. Researchers now suggest that people who suffer from depression and anxiety may develop Alzheimer’s at a younger age, earlier than those who do not have these conditions.
The analysis reveals that if people do develop Alzheimer’s disease, those with depression may start experiencing dementia symptoms about two years earlier than those who do not have depression. People with anxiety who develop Alzheimer’s may start experiencing dementia symptoms about three years earlier than those who do not have anxiety, according to the study that will be presented at the American Academy of Neurology’s 73rd annual meeting.
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The report also screened for any history of bipolar disorder, post-traumatic stress disorder, and schizophrenia. Of the 1,500 people in the study with Alzheimer’s, 43% had a history of depression, 32% had anxiety, 1.2% bipolar disorder, 1% post-traumatic stress disorder, and 0.4% schizophrenia.
“Certainly this isn’t to say that people with depression and anxiety will necessarily develop Alzheimer’s disease, but people with these conditions might consider discussing ways to promote long-term brain health with their healthcare providers,” advises study author Dr Zachary A Miller, from the University of California, San Francisco, and a member of the American Academy of Neurology.
One in 10 Americans aged 65 and older (10%) has Alzheimer’s dementia, and almost two-thirds of Americans with Alzheimer’s are women. About 5.8 million people in the US aged 65 years and older were estimated to be living with Alzheimer’s in 2020.
For their study, the team identified a “serial decrease in the age when symptoms first started that doubled with each additional psychiatric disorder diagnosis.” People with only one disorder developed symptoms about 1.5 years before those with no psychiatric disorders. Those with two psychiatric conditions developed symptoms 3.3 years earlier than those with no conditions. Those with three or more psychiatric disorders developed symptoms 7.3 years earlier than those with no such conditions.
“More research is needed to understand the impact of psychiatric disorders such as depression and anxiety on the development of Alzheimer's disease and whether treatment and management of depression and anxiety could help prevent or delay the onset of dementia for people who are susceptible to it,” recommends Miller.
Interactions between psychiatric disease and other risk factors for Alzheimer’s disease, such as high blood pressure, high cholesterol, and diabetes, were studied. The investigators also looked at factors that have more recently been associated with an increased risk for Alzheimer’s disease, such as having an autoimmune disease or a history of seizures.
People with depression and anxiety were more likely to be female and consistent with their younger age at onset, had fewer of the typical Alzheimer’s risk factors. However, those with depression were more likely to also have an autoimmune disease and those with anxiety were more likely to have a history of seizures.
“While this association between depression and autoimmune disease, and seizures and anxiety is quite preliminary, we hypothesize that the presentation of depression in some people could possibly reflect a greater burden of neuroinflammation. The presence of anxiety might indicate a greater degree of neuronal hyperexcitability, where the networks in the brain are overstimulated, potentially opening up new therapeutic targets for dementia prevention,” says Miller.