Based on the results of an analytical study, scientists from the Rotman Research Institute, a division of Baycrest Health Sciences, caution people that chronic stress and anxiety may lead to an increased risk for developing depression, and even dementia.
So what exactly is chronic stress?
Anxiety, fear and stress are common emotions and are considered a normal part of life. But only if they are occasional and temporary, such as feeling stressed and anxious before a job interview or an exam. However, when those acute emotional reactions become more frequent and long-lasting, their status changes to chronic stress.
To put it more scientifically, chronic stress is an abnormal state that is caused by an extended activation of a normal acute stress response. Chronic stress can wreak havoc on many systems in the body including the immune system, the cardiovascular system, and the central nervous system – atrophy of certain important areas in the brain.
As part of their project the researchers examined previous published articles on brain areas impacted by chronic anxiety, fear and stress in animal and human studies. From the data gathered, the authors of the study came to the conclusion that all three conditions cause a “great overlap” of the neuro-circuitry in the brain. This overlap could help explain the link between the development of neuropsychiatric disorders (including depression and Alzheimer’s disease) and chronic stress.
The details of the study can are posted in the online version of this month’s Current Opinion in Psychiatry.
According to lead author of the study Dr. Linda Mah, who is also a clinician scientist with Baycrest’s Rotman Research Institute and lead author of the review, chronic stress and pathological anxiety are associated with impaired functioning of the hippocampus and the prefrontal cortex (PFC) and also lead to structural degeneration. The combination of the afore-mentioned impaired functioning and structural damage could be the reason behind the increased risk of developing neuropsychiatric disorders.
As part of the study, Dr. Mah and her team examined recent data from studies of stress and fear conditioning in animal models, and neuroimaging studies of anxiety and stress in healthy individuals and in clinical populations.
They looked specifically at key the structures in the brain – amygdala, medial prefrontal cortex, hippocampus – which are affected during exposure to chronic stress. The researchers noted an overactive amygdala when the participants were subjected to fear/anxiety and chronic stress. On the other hand the thinking areas of the brain (PFC) that help regulate emotional responses through cognitive appraisal were under active.
Based on her findings, Dr. Mah suggests that stress-induced damage to the PFC and the hippocampus is not completely irreversible. In fact, anti-depressant treatment and physical activity have both proven effective in increasing hippocampal neurogenesis.
Buoyed by their findings the team is keen to do more work to determine whether interventions, such as exercise, mindfulness training and cognitive behavioral therapy, can help decrease the risk of developing conditions line dementia and Alzheimer’s disease.