Stress is something everyone experiences. Despite being unpleasant, stress in itself is not an illness. But there are connections between stress and mental health conditions including depression, anxiety, psychosis and post-traumatic stress disorder (PTSD).
Research into stress - its causes, effects on the body and its links to mental health - is vital. The more we understand stress, the better we can tackle it.
In this blog, we explore the science of stress and mental health. We look at how research is transforming what we know, providing hope for new treatments as well as showing effective ways to cope with stress in our everyday lives.
Fight or flight
Stress causes physical changes in the body. It increases heart rate and breathing. Muscles tense. Short-term memory becomes more effective. This stress response has evolved to keep us safe, as it prepares the body for ‘fight or flight’ when we sense danger. Research has also shown that thinking skills improve as stress increases. So, in short bursts, stress can be a good thing. It can help us prepare for a sports match, job interview or exam. Usually, after a stressful event, the body returns to its normal state.
Long-term stress
Many situations can cause a stress response in the body. Changes at work, illness, accidents, problems with relationships, family, money or housing can all cause stress. Even seemingly small daily hassles like someone pushing in a queue can make us feel stressed. What links all these situations is that we’re unable to predict and control what is happening to us, and so our body goes into a state of increased alertness. And these events can happen all the time - triggering the body’s stress response over and over again.
When the stress response becomes prolonged (chronic), it has a very different effect to the short bursts that enhance the body’s abilities. In many cases, the system controlling the stress response is no longer able to return to its normal state. Attention, memory, and the way we deal with emotions are negatively impacted. This long-term stress can contribute to both physical and mental illness through effects on the heart, immune and metabolic functions, and hormones acting on the brain.
Some of the emotional and behavioural symptoms of stress overlap with those of mental health conditions like anxiety or depression. This can make it hard to distinguish where one begins and the other ends, or which came first. Someone who is stressed may feel worried, down, unable to concentrate or make decisions, irritable and angry.
The biology of mental health and stress
Chronic stress increases the risk of developing depression and anxiety in some people. The precise mechanisms of how stress is linked to mental ill-health are being uncovered.
Scientists found that the earliest response to stress happens in the brain within seconds of perceiving a ‘stressor’. Chemicals which signal between nerve cells (neurotransmitters) are released. These include serotonin and adrenaline. Following this, stress hormones are released, which particularly affect areas of the brain key for memory and regulating emotions. Repeated stress changes how well these systems are able to control the stress response.
Researchers are also investigating how these systems are involved in anxiety and depression, suggesting a biochemical link between stress and mental illness. Recent studies have shown that long-term stress can change the structure of the brain, especially in areas supporting learning and memory. It can affect both nerve cells (grey matter) and the connections between them (white matter). It is possible these changes, along with other factors, can increase the likelihood of developing mental illness.
The immune system
Another link between stress and mental health is the immune system. During the stress response, the immune system is activated, helping to keep us safe. But chronic stress and prolonged activation of the immune system could negatively affect how the brain functions.
A prolonged activation of the immune system is also linked to depression. Researchers are working to understand how this activation can lead to depression and other types of mental illness in some people. About 30% of people with depression have increased immune activity in the body. Researchers are also undertaking clinical trials to find out if anti-inflammatory drugs might be able to help people with this kind of depression. Find out more about stress, the immune system and depression in our podcast.
Stress and PTSD
In some cases, short-term stress can also lead to a mental health condition. Post-traumatic Stress Disorder (PTSD) can develop after experience of an extremely traumatic or stressful event. Someone affected may experience vivid flashbacks or nightmares, and uncontrollable thoughts about the event. The exact causes of the condition are not clear - though some of the risk factors are understood.
State-of-the-art brain scanning has shown that, again, the areas of the brain particularly involved are the hippocampus and the amygdala. There is some evidence that the neurotransmitters and hormones involved in the normal stress response may become disrupted during and after the traumatic event. Research has also shown that the amygdala, which processes fear, is hyperactive in people with PTSD, perhaps creating a kind of “false alarm”.
Continued research offers the promise of new treatments for PTSD in the future.
Hope for the future
A key area for research is to understand why some people are much more affected by stress than others. A vast amount of research shows that genetics, early life events, and personality and social factors all have a role to play.
Understanding the biology of stress and its effects means that researchers can work towards new treatments. It could also help predict who is at risk of developing a mental health condition, and uncover the best time to intervene to help prevent ill-health later on.
Ways to help
There are lots of ways to help anyone who is stressed. The first advice is to try and identify the cause of stress and tackle it. Avoiding the problem may make it worse. Often it isn’t possible to change a situation and prevent stress. But, there are many ways to help control it, and stress management may be effective in improving health.
The NHS also has advice on different ways to beat stress, from exercise, to mindfulness and breathing exercises - all of which have been shown to help. Visit their site for more information.
If you’re looking for direct advice or help, our support section includes links to organisations that can help. There is also more information on specific conditions, including depression, anxiety and PTSD.
