Claustrophobia is a type of anxiety disorder, in which someone tends to show an irrational or intense towards enclosed spaces or fear of being put into a small place where there is no escape route. This is why you would see some people not feeling comfortable when confronted or when they find themselves in a very tight or enclosed place.
There are little known causes of claustrophobia. It has been researched that environment factors can cause claustrophobia. Also, Traumatic experience can also make someone to be claustrophobic, past experiences like getting stuck in a car or in a crowded space, being locked up in a small room can increase the probability of having claustrophobia.
It can also be caused as a result of amygdala dysfunction, a part in our brain that controls how we process fears. The effects of claustrophobia on people can be very dangerous unless it is upon very early.