Mental health in adolescents and adults: the role of gut bacteria in stress, anxiety and depression

When you're in a crowded place and looking around, maybe one in six people has experienced depression at some point in their lives, and one in 15-20 people may have experienced at least one severe depressive episode. Now, depression has become very common, more than 350 million people around the world are suffering from depression, the number of people suffering from depression in our country has reached more than 90 million, this number is expected to rise. In addition, globally, depression is the leading cause of the decline in working ability. It is estimated that depression could soon become the second most serious threat to human health, after heart disease. Like depression, anxiety spreads around the world like a plague. About 275 million people worldwide are believed to suffer from anxiety disorders.about stress, the vast majority of people say they experience stress often or sometimes through the day. The number of people under severe stress has increased by more than 100 per cent in just a decade, including an increasing number of children. There is no doubt that stress-related diseases have become an epidemic of our time, causing great damage to society and suffering to patients and their families. No one of us is immune to this.When we feel stressed, anxious or depressed, the activity in the brain is very similar, so they are often classified as stress-related disorders, which are the most common mental health problems in adolescents and adults. Occasionally low levels of stress are harmless, but prolonged stress can lead to a chronic stress state, which can lead to anxiety disorders such as panic disorder and various phobias. Persistent anxiety can also lead to depression. Now, a growing body of research suggests that gut bacteria are a decisive factor in stress-related disorders.stress and gut bacteriaaffecting more and more people. Stress is also thought to be the leading cause of death from cancer, coronary heart disease, accidental injuries, respiratory disorders, cirrhosis and suicide. Stress can also affect young people, with the number of children aged five to nine being diagnosed with stress more than double since 2006.stress has a positive effect when it is within a certain threshold, which can cause damage if it is exceeded. This threshold is related to factors such as genetic susceptivity, environment, disease, etc. Current studies have shown that the composition of gut bacteria affects our stress thresholds and our response to stress. On the contrary, stress also affects the composition of the gut bacteria.so, what is stress? In essence, stress is a necessary condition for survival. Everyone has stress, life pressure, work pressure and so on. Stress has become an integral part of our lives, and most people think it's natural.of all the definitions of stress that deserve our attention is a state of disharmony or a threat to the stability of the body. The steady state of the body here refers to the stable balance that all biological systems strive to maintain in their surroundings. In the case of body temperature, for example, our bodies constantly regulate certain body parts according to their surroundings to maintain a constant body temperature of 37 degrees. Hypothermia or hyperthermia can lead to death. Stress occurs when the body's balance is threatened. In other words, stress is evolution's response to threats to our steady state.A problem with acute stress Although stress is usually considered negative, in fact acute stress can be a good thing, in the animal world, we often see such footage, antelopes are chased by lions and run to death, faster than usual, do not run may immediately die, this is acute pressure, run away, this pressure is gone. In the face of such stress, in order to speed up the escape, many of the body's systems unrelated to coping with stress will slow down or even stop, giving more resources to escape to cope with stress. This is the natural reaction of living things and is not controlled by consciousness. So acute stress can help us escape danger., when the body is under prolonged stress and does not get rest, it becomes harmful. If we are under stress for a long time, the massive release of the stress hormone cortisol causes the hippocupus of the brain to shrink, which is not a good thing, because the hippocupus is important for memory and positioning function. Sadly, our ancient stress system (HPA axis) doesn't distinguish between real threats and false alarms, and when we experience something considered negative, our stress system releases stress hormones.chronic stress is a problem if it lasts too long and occurs too often, it opens the way to chronic imbalances, leading to more diseases. Symptoms of persistent stress may be physical (e.g. headache, stomach problems, sleep problems) or emotional (e.g. mood swings, loneliness), or mental (e.g. negative self-image) or behavior (e.g. diet, substance abuse). Several stress symptoms are also common. The symptoms of stress and the causes of stress vary from person to person, even at all moments. Long-term or chronic stress can easily translate into anxiety and depression, which negatively affects the gut microbioty and creates a vicious circle.stress promotes the growth of harmful bacteria in the gut stress hormones like epinephrine can revolutionized our gut bacterium by increasing the number of harmful gut bacteria and reducing the number of beneficial bacteria. Stress releases the stress hormone epinephrine from the adrenal glands, which accelerates our heart rate and raises our blood pressure. Epinephrine also stimulates the growth of harmful bacteria. In addition, epinephrine can even make these harmful bacteria more aggressive, increasing their chances of survival. Some bacteria can even turn epinephrine into a more harmful form of epinephrine, which can exacerbate the harmful effects of stress. As if that weren't enough, the harmful effects of stress on the gut bacteria can even alter some of the key signaling pathfages between the gut and the brain, leading to depression and anxiety.in general, short-term stress can be positive, and in our gut, acute stress increases the production of stomach acid and increases the chance that harmful bacteria will die before reaching our gut. However, once acute stress becomes chronic, the benefits become bad. Stress hormones are at unhealthy levels in the blood and can harm our bodies in different ways. Low levels of stress are harmless, but prolonged excess stress can be dangerous, especially for our gut bacteria and brain.stress causes intestinal leaks stress hormones reduce the thickness of the intestinal mucosa, leading to intestinal leakage. This, in turn, makes it possible for toxic bacteria to pass through and touch intestinal immune cells, and the intestinal immune system is activated immediately, leading to increased inflammation. The stress-intestinal leak-inflammation pathway has been shown to be associated with depression and many other brain-related diseases. Simply put, stress has a harmful effect on our intestinal and brain axes.early life stress will shape our gut bacteria the harmful effects of stress on the gut bacteria seem to shift from mother to child. A study showed that women who experienced high levels of stress during pregnancy had fewer beneficial bacteria in their gut virlobis than women who did not experience high levels of stress, and that these children often had other health problems, such as allergies and intestinal problems. In animal models, there is a more brutal way to study the effects of stress on gut microbiotics by separating them from their mothers early in life. Studies have shown that mice removed from their mothers at birth still have high levels of the stress hormone cortisol as adults. Similar studies have shown that premature separation from the mother can lead to long-term changes in gut microbioty, stress conditions, and behavior.the stress response of gut bacteria some exciting studies have shown that certain lactic acid bacteria can lower stress hormone levels in these stress mice. In fact, all abnormalities in the brain disappeared completely when traumatized mice separated from their mothers were replenished with lactic acid bacteria at an early age. Researchers now believe that bacteria planted in the gut immediately after birth initiate important mechanisms in the brain to deal with stress and emotional behavior. In addition to mice that were separated from their mothers after birth, sterile mice that did not carry any bacteria were also sensitive to stress and exhibited "unsymloy" behavior. However, these stress symptoms also disappeared when lactic acid bacteria were replenished.the infant Bifidobacteria in sterile mice was enough to calm their brains. When the researchers transplanted the feces of calm mice into highly stressed sterile mice, the stress mice calmed down; , depression and gut bacteria anxiety and depression are closely related, and long-term anxiety translates into depression, while many people suffer from both anxiety and depression. Therefore, anxiety is one of the symptoms of depression diagnosis. People with anxiety and depression also have some common physiological conditions, such as stomach problems, sleep problems, increased inflammation, lower levels of brain-sourced neurotrophic factors (especially in memory-related brain regions), high cortisol levels, increased stress response, and increased bowel leakage. Arguably, the main difference between anxiety and depression is that anxiety is an excessive fear and fear of the future, while depression is more of a sense of meaninglessness and despair, focusing on what happened before. If a person with anxiety is worried about "the end of the world", then depressed people will feel that "the end of the world has come". anxiety is similar to stress, anxiety is also a natural response, and experiencing anxiety doesn't necessarily mean something's wrong. The stress symptoms we experience when we feel anxious are caused by our bodies' responses to something that seems threatening. The body prepares for this by increasing levels of epinephrine and other stress hormones in the blood. Symptoms of anxiety are shown by increased stress, including muscle contraction, faster heartbeat, and more rapid breathing. Breathing difficulties, suffocation sensations, difficulty swallowing, stomach problems, chest pain, dizziness and nausea are also common. Psychologically, anxiety manifests it as inattmentality, fatigue, uncontrollable anxiety, and so on. Usually, an anxiety episode subsides on its own, but when anxiety persists and causes great pain, greatly reducing a person's quality of life, it becomes a mental illness and falls into the category of anxiety disorder. are signs of depression? Typical symptoms are depression, feeling empty, feeling meaningless, and finding it difficult to find happiness in everyday life. It is sometimes normal for us to feel depressed, and this emotion usually disappears on our own, but when depression persists for weeks or months, leading to a significant decline in a person's quality of life, it becomes depression. It's a bit tricky to know exactly the line between low-mood natural feelings and mental disorders. In addition, depression has many different symptoms, such as low mood, guilt, sadness, anxiety, insomnia, fatigue, lack of energy, meaninglessness, physical pain, constipation, menstrual disorders, decreased libido, inattence, memory loss, lack of appetite, and so on. Depression can also lead to suicidal thoughts and even suicidal behavior. In fact, depression is the biggest risk factor for suicide. According to the World Health Organization, the global suicide rate is around 145 per 100,000, and about 1 million people die each year. According to statistics, about 250,000 people die each year from suicide in China, the number of suicide attempts is about 2 million, suicide has become the fifth leading cause of death in China's population, is the first cause of death of young adults aged 15-34 years old. depression a chemical imbalance in the brain or inflammation in the brain? that changes in the balance between different neurotransmitter in the brain can lead to depression. Depression is usually associated with lower levels of 5-serotonin. Therefore, antidepressants work mainly by raising levels of 5-serotonin in the brain. The problem with drugs like Persymic that raise levels of 5-serotonin (selective 5-serotonin reuptake inhibitors) is that they can take weeks to show any positive effects. Until then, symptoms may get worse and may have side effects. If solving depression is only by raising levels of 5-serotonin in the brain, then these drugs should have an immediate effect, so obviously not. that depression may be caused by a chemical imbalance in the brain is being challenged by a very different view. Depression may be linked to inflammation of the brain, new research suggests. Inflammation of the body can spread to the head, and the more inflammatory substances around the body, the more severe depression seems to be. other studies, including one that showed inflammation of brain tissue in patients with chronically untreated severe depression. Inflammation levels were 33 percent higher in certain areas of the brain than in patients who had taken the drug. As a result, many researchers believe that some depression may be the result of inflammation. The use of antidepressants can prevent inflammation of nerve cells. As a result, researchers are also studying the possibility of using anti-inflammatory drugs to treat people with depression. is the relationship between depression and the intestinal that induce inflammation, depression, inflammation, and gut bacteria? When researchers injected healthy mice with lipid polysaccharies (LPS), which can cause inflammation, they immediately developed symptoms similar to depression. The LPS here is the cell wall component of harmful bacteria, which can cause leaks in the intestines. In addition, substances that cause inflammation in the intestines can lead to an increase in LPS production, which can lead to an increase in intestinal wall permeability. People with depression often show inflammation of the intestinal wall and increased intestinal permeability. Once LPS enters the bloodstream, it crosses the blood-brain barrier and reaches our brain, causing inflammation in the brain. addition to depression, inflammation increases the risk of late-life Alzheimer's disease. Compared to healthy people, people with depression had much higher levels of LPS, and those with Alzheimer's had three times higher levels of LPS than normal people. Some researchers even believe that people with depression are twice as likely to develop Alzheimer's disease or severe cognitive impairment as normal people. people with depression have any