There is an “extensive overlap” of the brain’s neural activity in anxiety, fear and stress which may explain the link between chronic stress and the development of neuropsychiatric disorders — mental disorders, including depression and Alzheimer’s disease, the findings showed.
Chronic stress is a pathological state that is caused by prolonged activation of the normal acute physiological stress response, which can wreak havoc on immune, metabolic and cardiovascular systems, and leads to degeneration of the brain’s hippocampus (crucial for long-term memory and spatial navigation).
“Pathological anxiety and chronic stress are associated with structural degeneration and impaired functioning of the hippocampus which may account for the increased risk of developing neuropsychiatric disorders, including depression and dementia,” said lead author Linda Mah, an assistant professor at the University of Toronto in Canada.
Experiencing anxiety, fear and stress is considered as a normal part of life when it is occasional and temporary, such as feeling anxious and stressed before an exam or a job interview.
However, when these acute emotional reactions become more frequent or chronic, they can significantly interfere with day-to-day activities, warned the researchers in the paper published online in the journal Current Opinion in Psychiatry.
The review also suggested that stress-induced damage to the hippocampus is “not completely irreversible”, concluded Mah.
The review paper examined recent evidence from studies of stress and fear conditioning in animal models, and neuroimaging studies of stress and anxiety in healthy individuals and in clinical populations.