You may have experienced a situation in which, after a prolonged period of tension, even performing ordinary tasks becomes difficult. You find it hard to concentrate, forget important information, and take longer than usual to make decisions.
This may be more than just a result of fatigue. Prolonged stress can affect the neural networks responsible for memory, attention, and emotional regulation.
November 2–6 marks International Stress Awareness Week. Its aim is to raise public awareness of the effects of stress and highlight the importance of looking after mental health.
As part of this week, we have already discussed how the body responds to stress. This time, let’s focus on another question: what happens to the brain when stress persists over a long period? Can prolonged stress change the brain’s structure, and to what extent can it recover afterward?
How Does Stress Affect Memory?
One of the brain structures affected by chronic stress is the hippocampus.
The hippocampus plays a role in forming new memories, processing information, and spatial navigation. It helps us remember where we left our keys or what we learned the previous day.
Studies in animals have shown that prolonged stress can alter the structure of neurons in the hippocampus. Specifically, the dendrites of some neurons become shorter. These are the branches through which neurons receive signals from other nerve cells.
The number and efficiency of connections between neurons may also change.
This matters because memory is not simply about storing information. Its functioning depends on the interactions between nerve cells.
Studies in humans have also identified associations between prolonged stressful experiences and structural characteristics of the hippocampus. However, such an association does not necessarily mean that stress directly caused these changes.
Why Does Making Decisions Become More Difficult?
Chronic stress affects more than just memory.
Another important brain region is the prefrontal cortex, which plays a role in planning, attention control, decision-making, and impulse regulation.
It helps us evaluate different possible courses of action, consider their potential consequences, and focus on long-term goals.
Under prolonged stress, the neural connections and functioning of this region can change. As a result, people may sometimes struggle to concentrate on complex tasks, take new information into account, or reconsider decisions they have already made.
For example, they may make more mistakes when performing familiar tasks or find it harder to approach problem-solving flexibly.
This is related to cognitive flexibility — the ability to adjust our thinking and behavior in response to changing circumstances.
Why Might the Brain Become More Sensitive to Threats?
Stress-related changes also affect the amygdala. This structure is involved in processing emotionally significant information and plays a particularly important role in learning about threatening experiences.
According to some animal studies, chronic stress can strengthen connections between neurons in certain parts of the amygdala.
Interestingly, these changes are not the same across all brain regions: the branches of some neurons in the hippocampus and prefrontal cortex may become shorter, while opposite changes can occur in certain amygdala networks.
As a result, the body may become more alert to potential threats. From an evolutionary perspective, this adaptation could be beneficial under certain circumstances. When danger is constantly present, recognizing it quickly increases the chances of survival.
The problem arises when this heightened state of alertness persists even in safe environments.
Can the Brain Recover?
To answer this question, one concept is particularly important — neuroplasticity!
Neuroplasticity is the brain’s ability to change its structure and functioning in response to experience and environmental conditions. This property allows us to learn, acquire new skills, and recover certain functions following some forms of injury.
Some changes caused by chronic stress may also be reversible. For example, animal studies have shown that after stressful conditions end, neuronal branches in the hippocampus can grow again, while certain impairments in spatial memory may improve.
A scientific review published in 2018 examined this process. According to the authors, recovery does not always mean simply returning to the original state. The brain can develop new adaptive changes to improve its functioning.
Assessing the possibility of full recovery in humans is more complicated. Outcomes depend on the duration of stress, age, experiences, health status, and individual characteristics.
Early life is particularly important. Numerous studies have identified associations between severe childhood stress and structural characteristics of certain brain regions.
This does not mean that experiencing stress during childhood necessarily causes irreversible changes in the brain. Research simply suggests that early experiences can sometimes leave long-lasting effects.
What Does This Mean for Us?
Chronic stress does not necessarily mean inevitable brain damage. People differ in their resilience, and the brain retains its ability to change and adapt throughout life.
Reducing sources of stress, getting enough sleep, engaging in physical activity, maintaining social support, and seeking professional help when necessary may all support recovery.
The important thing to remember is that our brain is not a static organ. It is constantly changing through its interaction with the environment.
Prolonged stress can push these changes in an unfavorable direction, but thanks to neuroplasticity, the brain also retains a significant capacity to adapt and improve its functioning.
