While it's easy for most people to understand how stress and worry can cause physical symptoms, like aches and pains, or emotional symptoms, like moodiness and irritability, it's more difficult to understand the impact of stress on memory.
What is Stress?
Stress is a normal response to threatening or dangerous events. Our stress response (also called the fight-or-flight response) can give us a jolt of energy, strength, focus, and alertness to help in emergencies. But when stress becomes chronic, it stops being helpful and leads to adverse effects on our bodies, minds, and emotions. The brain is an excellent example of how chronic stress leads to problems with learning and memory.
Relationship Between Stress and Mental PerformanceOn a chemical level, low to moderate levels of stress hormones like cortisol and adrenaline can improve memory, while higher levels seem to disrupt memory. Stressors can produce narrowing or even lapses in attention, and it may take longer to make decisions. If you're not able to concentrate on a subject in the first place, you won't remember it later.
With chronic stress, hormones that turn on the fight-or-flight response, like adrenaline, may remain active in your brain too long. This may eventually injure and even kill cells in the hippocampus, a brain area critical for memory and learning. Interestingly, it is the hippocampus that is affected early on in Alzheimer's disease.
High levels of cortisol due to chronic stress seem to induce depression as well. The connection between depression and memory loss has been known for years, with a leading theory being that during periods of stress, the high levels of cortisol that are produced cause damage to connections between brain cells. In fact, Dr. George Alexopolous, a psychiatry professor at Cornell University, told the Wall Street Journal that "depression creates a tremendous burden to a brain that already had increased predisposition to dementia." People with low levels of stress in their lives are likely better able to tolerate age-related brain changes.
Caregiver Stress Affects MemoryCaregiver stress in dementia is so common I suspect it is rare for it to be absent. Signs include social withdrawal, anxiety, depression, exhaustion, and even anger at the person with dementia. Remarkably, one study found that the caregiving spouse had a six fold increase in dementia risk compared with subjects whose spouses did not have dementia. This risk was identical for men and women.
Stress Management is the KeyIt is unrealistic to eliminate all stress from your life. Rather, the key is managing stress so that it doesn't spiral out of control and affect your functioning. Managing stress includes:
- identifying the source of stress
- taking better control of your reactions, thoughts, and emotions
- taking better care of yourself
- making time for rest and relaxation
A strong network of supportive friends and family members is also important, as is education and knowledge about the stressful situations. Mental health professionals may be helpful as well.
McEwen, Bruce, "Protection and Damage From Acute and Chronic Stress" Ann. N.Y. Acad Sci. 2004; 1032: 1-7.
Norton, Maria C., Smith, Ken, Ostbye, Truls et al., "Spousal Dementia Caregiving as a risk factor for incident dementia?" Alzheimer's & Dementia 2009 July; 5(4) [suppl]: 380-381.
University of Southern Mississippi: Behavioral Neuroscience. "Stress and Cognition." Accessed: March 17, 2010
Wang, Shirley S. "How Depression Weakens the Brain." Wall Street Journal, July 3, 2007. Accessed: March 17, 2010.