The brain's response to fear and anxiety
Fear is a deeply wired response that has evolved to protect us from perceived threat and promote our survival. It's not limited to us humans, it's a response shared by all species - well the ones that have managed to survive anyway. Which comes as no surprise if you consider the adaptive nature of this function - put simply, it is our threat detection system that enabled us to survive in earlier, much more primitive and comparatively much more dangerous times.
While it might not feel like it at the time, the fear response is a reaction that actually starts in the brain. From here it spreads through the body, triggering it to produce the best defence mechanisms to protect us (also known as the fight/flight/freeze response). Once incoming messages have been received by the brain signalling imminent threat, this triggers the fear response in a part of the brain called the amygdala, which, in a primitive way, is responsible for detecting and responding to threat.
Should a fear response be triggered in the amygdala, this then activates those areas in the brain which stimulate the motor functions involved in the fight or flight response. The amygdala will also trigger the stress hormones being released into the body, and the activation of the sympathetic nervous system.
All of this combines to prepare us for action and making us ready to deal with danger. Consequently, the brain becomes hyper-alert, our pupils dilate, our breathing accelerates, our heart beats faster and our blood pressure rises. Blood flow increases, as does the supply of energy to muscles needed for fight and flight. Organs in our bodies not required for our safety are slowed down, and the energy diverted away from them is redistributed to areas where this is much more necessary.
The hippocampus and prefrontal cortex areas are the most recently evolved areas of our brain, and they help us to interpret any perceived threats from a more intellectual perspective. This is the “thinking” circuitry of our brains. Their higher-level processing of incoming information enables us to determine whether or not a perceived threat presents real danger. But sometimes incoming threat information can bypass this more intelligent area of the brain, and be processed directly by more primitive areas of our brains, hence why our thoughts and fears can be irrational. And what can result from this primitive processing are abnormal levels of fear and anxiety, leading to significant distress. Higher levels of distress can be problematic should they persist, and can result in dysfunction which in some cases can significantly inhibit the extent to which we are able to live our lives.
If you are struggling with anxiety then it's important to seek help before this issue continues to disrupt the quality of your life. Effective treatments, such as psychotherapy and medication are available and work in a relatively short timescale. NICE guidelines indicate cognitive behavioural therapy (CBT) as the preferred option for treating anxiety problems. Always check your psychotherapist is fully qualified in CBT. You can check the BABCP's website or search for a therapist on Counselling Directory.