It is well established that people with mild cognitive impairment are at higher risk of developing Alzheimer’s disease later in life. Now, a new study suggests that experiencing anxiety alongside mild cognitive impairment can further increase this risk.
Mild cognitive impairment (MCI) is described as changes in cognitive function – such as memory and thinking skills – that can be noticed by others or the individual experiencing the changes, but these are changes that are not severe enough to disrupt day-to-day life.
According to the Alzheimer’s Association, studies estimate that around 10-20% of people aged 65 and older have MCI. Many individuals with MCI go on to develop Alzheimer’s disease within a few years of diagnosis. But this latest study, published in The American Journal of Geriatric Psychiatry, suggests that anxiety speeds up cognitive decline in people with MCI, meaning they may develop Alzheimer’s at a much faster pace.
According to the research team – including principal investigator Dr. Linda Mah, an assistant professor in the Department of Psychiatry at the University of Toronto and a clinician-scientist at the Baycrest Health Sciences’ Rotman Research Institute, both in Canada – there is growing evidence indicating that late-life depression may be an important risk factor for Alzheimer’s, and anxiety has been linked to depressive disorders.
However, Dr. Mah and colleagues note that no studies have looked specifically at how anxiety influences progression to Alzheimer’s in patients with MCI. As such, they set out to investigate this association. Over an average of 3 years, the team analyzed 376 patients aged 55-91 with amnestic MCI – characterized by the inability to recall important information, such as appointments, recent events or conversations – who were a part of the Alzheimer’s Disease Neuroimaging Initiative (ADNI).
Every 6 months, the researchers assessed participants’ levels of anxiety and depression, as well as changes in cognitive functioning and brain structure.
Results of the analysis revealed that participants who had anxiety experienced a faster decline in cognitive function than those without anxiety, and that the speed of decline increased with the severity of anxiety. MCI patients with mild anxiety had a 33% increased risk of Alzheimer’s, moderate anxiety was linked to a 78% Alzheimer’s risk, while severe anxiety increased Alzheimer’s risk by 135%.
What is more, the team found that participants who reported symptoms of anxiety at any point over the study period showed higher levels of brain atrophy – brain shrinkage – in the medial temporal lobe regions, which are crucial for creating memories. Atrophy in these brain regions has been implicated in Alzheimer’s. The researchers note that all participants had low scores on the depression scale, suggesting that their findings were not a result of clinical depression.