What causes PTSD?
While the initial cause of PTSD will often be clear after a particularly traumatic event, it's not yet known why some people go on to develop the disorder, while others experiencing similar circumstances don't.
It's unlikely you'll be diagnosed with PTSD if you go through upsetting situations such as a divorce, being made unemployed, or not passing an exam, although you may still experience some symptoms that are closely related to the condition.
Risk factors
Other factors that are believed to contribute to the development of PTSD include having a history of or existing mental health conditions such as anxiety and depression. Having a lack of social support after the event can also exacerbate feelings of confusion, frustration and isolation, which can increase your chances of experiencing symptoms of the condition.
Reasons for development
Theories for why PTSD develops in some but not others experiencing the same or similar levels of trauma include:
- Survival mechanism - while anyone who's experienced a traumatic or stressful event will develop natural stress reactions as the brain learns to cope and protect the body from extreme shock, people with PTSD may have an exaggerated version of this ‘survival mechanism’ response
- High adrenaline levels - studies indicate that if you've been diagnosed with PTSD, you'll have unusually high amounts of stress hormones in your body, which causes some of the extreme physical and emotional symptoms that are common in the disorder, such as feelings of numbness and the hyperarousal associated with the fight or flight reaction. Your body will continue to produce the hormone even when there's no obvious danger
- Changes in the brain - brain scans of people with PTSD show that parts of your brain responsible for emotional processing are different than those with the condition. The hippocampus area of the brain is known to store memories and control emotional responses. This area appears to be smaller in people with PTSD, which possibly explains the disrupted link between fear, anxiety, memories and reliving the traumatic event which isn’t being correctly processed
If PTSD is left untreated, these symptoms can become severe and long-lasting which can affect your family, social and work life.
The difference between expected levels of stress and anxiety after trauma depends on how long initial symptoms last. If you have PTSD, they can last beyond a few weeks and may not improve until you get professional medical help and support.
Why does PTSD happen?
The ICD10 classification for PTSD (F43.1) states:
- The disorder arises as a delayed response to a stressful event or situation, (of either brief or long duration) of an exceptionally threatening or catastrophic nature, which is likely to cause pervasive stress in almost anyone
- Upsetting situations that are described as ‘traumatic’ in everyday language, e.g. divorce, loss of a job or failing an examination are better classified as (F43.2) adjustment disorder
CPTSD is said to arise where there has been repetitive, prolonged trauma involving sustained abuse or abandonment by a caregiver or other interpersonal relationships with an uneven power dynamic.
In response to acute stress, the body's sympathetic nervous system is activated due to the sudden release of hormones, triggering the release of catecholamine. This leads to a state of hyper-arousal, commonly known as the ‘fight or flight’ response. When people experience trauma, the world may then feel like a less secure place and the trauma may re-invoke earlier feelings of vulnerability.
Some people with PTSD are said to show organic and functional abnormalities of the brain. Areas implicated include the amygdala, hippocampus and pre-frontal cortex.