How Chronic Stress Affects the Brain

In the hit comedy “Analyze This,” mob boss Paul Vitti is incredulous when his therapist tells him that stress could be the cause of his panic attacks and depression. The humor, of course, is that stressors in Vitti’s particular line of work are not the same in most others, but it does beg an interesting question; how potent is stress?

The short answer is: extremely.

While most of us would easily recognize the physical manifestations of stress: fatigue, anxiety, restlessness, these are only the surface signs of a much stronger physiological reaction.

Stress can refer to any set of stimuli (internal or external) that disrupt our homeostasis, or overall sense of balance and tranquility. The stress response refers to the physiological effects that result from the stimuli.

For example, a stressful stimulus could come in the form of an upcoming exam we are required to take. Our brains recognize that the test is an unpleasant task. This causes a chain of interactions in what’s called the “hypothalamus pituitary adrenal axis” or HPA axis. The brain sends signals to the endocrine system which begins producing a hormone called cortisol. The physical symptoms we associate with “being stressed” are the direct result of the increase in cortisol and its effect on our bodies.

This response is both common and healthy. Our brains prepare our bodies for stressful stimuli and when the stimuli have passed, we enjoy feelings of relief.

But what happens when the stressful stimuli don’t go away?

Chronic or continuous stress refers to stressful stimuli that remain present over longer periods. Since the stimuli don’t disappear, our brains continue sending signals for a stress response. In other words, instead of taking the exam and then feeling relief that it is over, we continue to feel the apprehension without getting the sense of relief.

If this sounds unpleasant, that’s because it is.

Chronic stress affects the human brain to such a degree that the size, structure, and even basic brain functions may be altered.

Short-term stress leads to increased levels of cortisol, which then decreases when the stress passes. Chronic stress, however, leads to ongoing elevated levels of cortisol, which in turn increases the number of connections in the amygdala, the fear center of the brain. It also leads to a deterioration in signals sent out by the hippocampus, the brain’s center for memories, learning, and stress control. Since the hippocampus is responsible for keeping the HPA axis in check, our ability to cope with future stress is decreasing as well. This combined with increased cortisol shrinking the prefrontal cortex, the decision-making center, leads to increased sensitivity

to stressful stimuli, difficulty in maintaining focus as well as a marked lowering of our brain’s ability to cope.

The long-term effects of these developments are serious and include a greater likelihood to develop depression and even neurological disorders like Alzheimer’s Disease.

Unfortunately, these effects are not limited to our own brains. The ability of our bodies to produce enough cortisol receptors, or the tools used to neutralize cortisol is hampered by chronic stress. So not only are our bodies busy trying to respond to stress that lingers, the stress itself compromises our ability to deal with that stress.

When the number of cortisol receptors decreases, the higher level of cortisol then leads to what are called epigenetic changes. Essentially, certain genes become more prominent than others and the likelihood of them then being passed down to offspring increases. This means that a person who struggles with chronic stress is much more likely to produce children who will also have difficulty coping with stress. What’s more, as a hereditary trend, this will extend beyond one or two generations.

The bottom line?

Chronic stress affects our brains’ size, structure, and functions. What’s more, the effects can be permanent and can be passed down to our children.