From making you more forgetful to increasing your risk of dementia, here are 12 things that chronic stress does to your brain

11/01/2018 / By Ellaine Castillo

Every day, people encounter things that stress them out, whether it be school, work, or even other people. Because it is so common to experience stress, many people have come to accept it as a constant part of their lives and have stopped trying to alleviate it. However, this should not be the case since constantly being stressed can be very harmful to the brain.

Stress is classified into two major types: acute or chronic. Acute stress, which is also known as the “fight or flight” response, is generally harmless and can even be beneficial. This is caused by the stress hormones adrenaline and norepinephrine that are especially helpful during emergencies. Once there is no more need for these hormones, the body immediately gets rid of them. On the other hand, chronic stress produces cortisol. This hormone, unlike adrenaline and norepinephrine, stays in the body for much longer. Because of this, it can be very damaging to the body, especially to the brain. The many ways through which chronic stress and cortisol affect the brain include the following:

Generation of free radicals — Cortisol stimulates an increase in the amount of glutamate produced. This is harmful because glutamate creates free radicals, molecules with an unpaired electron that are highly reactive to other substances. These molecules attack brain cells by poking holes in their cell membranes, causing them to rupture and die. Changes in lifestyle that are associated with stress, such as loss of sleep, increase in junk food and alcohol intake and smoking cigarettes, also increase free radicals.
Forgetfulness and mood swings — People who are stressed tend to easily forget things because brain signals associated with memory are weakened. In contrast to this, signals linked to mood are strengthened so people also experience emotions more strongly.
Fear and anxiety — The amygdala is the part of the brain responsible for causing fear. Under chronic stress, activity from this brain region is heightened because of an increase in size and the number of cell connections.
Inhibition of brain cell production — Brain cells don’t last forever. Eventually, they’ll die off, and they would have to be replaced by new ones. The brain-derived neurotrophic factor (BDNF) is responsible for this renewal. However, cortisol prevents BDNF from being produced, consequently reducing the number of new brain cells formed. If BDNF levels are not returned to normal, it can lead to health problems like depression, obsessive-compulsive disorder, schizophrenia, dementia, and Alzheimer’s.
Depression — Under chronic stress conditions, the brain produces less of the neurotransmitters serotonin and dopamine, which are known as the “happy molecule” and the “motivation molecule,” respectively. Reduced levels of these neurotransmitters lead to different types of depression. Depression caused by dopamine deficiency leads to low motivation, lethargy, and reduced enjoyment of life. Meanwhile, serotonin-based depression affects overall mood, causing anxiety and irritability.
Increased risk of mental illnesses — Although the cause of mental illnesses are not yet well understood, studies have shown that the brains of people experiencing chronic stress are physically different from the brain of those who aren’t stressed. This alteration increases the risk of mental illnesses like anxiety, post-traumatic stress disorder, schizophrenia, bipolar disorder, and addiction.
Impaired cognition — People who are stressed often find it more difficult to think. This happens because the “fight” response for survival is triggered, causing instincts to take precedence over rational thought and reasoning.
Smaller brain size — The presence of cortisol negatively affects the size of the brain, especially the hippocampus and the prefrontal cortex, by killing and preventing the regeneration of neurons.
Vulnerability to neurotoxins — Normally, the brain is vulnerable to toxins, but with the help of the blood-brain barrier, it is able to keep harmful substances away. When people are stressed, the blood-brain barrier becomes easier to penetrate so harmful substances find it easier to get to the brain. Because of this, the risk of brain cancer, infections, and multiple sclerosis increases.
Higher risk for dementia and Alzheimer’s — Many people fear being diagnosed with Alzheimer’s disease, especially now that it has become the sixth leading cause of death. Studies have found that chronic stress, especially during midlife, increases the chance of developing Alzheimer’s. Furthermore, chronic stress is also a risk factor for dementia.
Death of brain cells — Chronic stress causes brain cells to stop dividing by significantly shortening telomeres, which are protective caps at the end of the chromosomes. This consequently leads to cell death.
Brain inflammation — The brain has its own immune system in the form of microglia. Unlike other immune cells, microglia cannot be turned off once it has been activated so it continues to create inflammation until it dies. Chronic stress is one of the common triggers for microglia activation.