Chronic stress and anxiety may increase the risk for developing depression and even dementia, a new study warns.

Experiencing anxiety, fear and stress is considered 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 those acute emotional reactions become more frequent or chronic, they can wreak havoc on immune, metabolic and cardiovascular systems, and lead to degeneration of the brain's hippocampus, the part of the brain  crucial to long-term memory, previous research has shown.

In a new review article, a Canadian research team evaluated human and studies examining brain areas impacted by chronic anxiety, fear and stress. They noted similar patterns of abnormal brain activity in regions of the brain are impacted with exposure to fear/anxiety and chronic stress – specifically an overactive amygdala (associated with emotional responses) and an under-active PFC (thinking areas of the brain that help regulate emotional responses through cognitive appraisal).

This seesaw relationship was first identified in a landmark study over a decade ago. 

However, the study, which appears in Current Opinion in Psychiatry, also suggests that this stress-induced damage is not completely irreversible as anti-depressant treatment and physical activity have both been found to generate new brain cells in these affected areas.