I went on a learning course re panic attacks many years ago and it helped me best understand them.
This is my best shortened down version of what was explained
and my own interpretation of that from my experiences.
The origin of an the panic attack is primal
Lets say neandethal man went out hunting, heard a rustle in the bushes
and out popped a sabre toothed tiger.
response 'flight or fight'
kicks in spontaneously in reaction
to the event of danger
The heart pumps faster and all the physical and chemical reactions of fear kick in , in response.
This primal response is required in order to overcome the danger and fight and win and save his life.
Which he does
He fights andn kills the tiger and goes back to the village and happyly carries on with life.
On another occassion he goes out again and hears again the 'rustle of the bushes'
Now instead of considering if the rustling sound is
1. The Wind
2 . A sabre toothed tiger
His body reacts , its automatically triggered into pure fear, heart pumps, mouth drys etc etc.
This is in essence what we call a panic attack.
The reason he needs to 'panic' is motivational and saves his life.
Interestingly and natrually he does not stop to 'consider'
for one millesecond if the sound of the bushes is ' the rustling of the wind'
Thinking could delay the response and get him killed.
The body is programmed to respond not to think about possible wind theories.
The brain has learned something.
The 'rustle' of the bush means danger.
He will panic when he hears this sound despite himself.
Its a primal switch or trigger necessary to save his life.
Luckly for us we dont have sabre tooth tigers jumping out of bushes to contend with but we do of course have events that we are or at the very least 'feel' threatened by in our lives.
Unfortunately the switches can get turned on when we do not need them, a bit like a faulty car alarm going off.
A panic attack can be just that , an alarm system that is not required but none the less is a real event of pure fear and terror.
There was an example of how a man was being treated by the person doing this course for problems he encountered emotionally.
The man had been in a huge train crash we had in the UK.
He had huge panic attacks when he went to go out of his house and saw moving cars and then eventually went onto cars merely parked outside .
He became agrophobic.
So he had an obvious phobia to cars.
The instructor explained how the car being made of metal represented the metal in the train and the 'speed' was also representative.
The trigger was the metal and speed to elicite a panic attack.
The man from the crash was a statician and knew all the logic and numbers of the likely hood of being hit by a fast moving car but this made no difference.
He simply reacted despite logic and despite himself.
This is a simple example of how a panic attack can work.
They can and do become more complex.
I will try and write more later