What causes PTSD?

PTSD is essentially a memory filing error caused by a traumatic event. When you experience something really traumatic your body suspends ‘normal operations’ and so temporarily shuts down some bodily functions such as digestion, skin repair and crucially, memory processing.

During trauma, your brain thinks ‘processing and understanding what is going on right now is not important! Getting your legs ready to run, your heart rate up, and your arms ready to fight this danger is what’s important right now, I’ll get back to the processing later.’

As such, until the danger passes, the mind does not produce a memory for this traumatic event in the normal way. So, when your brain eventually does go back to try to process the trauma, and the mind presents the situation as a memory for filing, if finds it ‘does not exist’ in your memory yet, so it sees it as a situation in the current timeline, and so it can be very distressing.

The distress comes from the fact that the brain is unable to recognise this as a ‘memory’, because it hasn’t been processed as one. As such, the facts of what happened, the emotions associated with the trauma and the sensations touch, taste, sound, vision, movement, and smell can be presented by the mind in the form of flashbacks – as if they are happening right now. The distress during the traumatic event, and this continued distress is what causes that changes in the brain, and the subsequent symptoms of PTSD. 

Complex PTSD

There is a second, subtype of PTSD, called Complex PTSD, or C-PTSD. This is usually a result of repeated, or sustained traumas, and presents in a similar way to PTSD, but with some additional symptoms too. Any of the causes noted above (and many others) can cause C-PTSD if they have been experienced repeatedly, or if someone has experience a number of different traumas.  You can find out more about C-PTSD in children and young adults specifically here.