Claustrophobia is the fear of confined spaces. It can be triggered by many situations or stimuli, including elevators, especially when crowded to capacity, windowless rooms, and hotel rooms with closed doors and sealed windows. Even bedrooms with a lock on the outside, small cars, and tight-necked clothing can induce a response in those with claustrophobia. It is typically classified as an anxiety disorder, which often results in panic attacks. The onset of claustrophobia has been attributed to many factors, including a reduction in the size of the amygdala and classical conditioning. One study indicates that 5–10% of the world population is affected by severe claustrophobia, but only a small percentage of these people receive some kind of treatment for the disorder. The term claustrophobia comes from Latin claustrum "a shut in place" and Greek φόβος, phóbos, "fear". Signs and symptoms
Claustrophobia is classified as a mental and behavioral disorder,  specifically an anxiety disorder. Symptoms generally develop during childhood or adolescence. Claustrophobia is typically thought to have one key symptom: fear of suffocation. In at least one, if not several, of the following areas: small rooms, MRI or CAT scan apparatus, cars, buses, airplanes, trains, tunnels, underwater caves, cellars, elevators and caves. Being enclosed or thinking about being enclosed in a confined space can trigger fears of not being able to breathe properly, and running out of oxygen.
A child gets separated from their parents in a large crowd and gets lost. A child sticks their head between the bars of a fence and then cannot get back out. A child crawls into a hole and gets stuck, or cannot find their way back. A child is left in their parents car, truck, or van. A child is in a crowded area with no windows (a classroom, basement, etc.) and has run-ins with other people, or is put there as a means of punishment.The term past experiences, according to one author, can extend to the moment of birth. In John A. Speyrers "Claustrophobia and the Fear of Death and Dying", the reader is brought to the conclusion that claustrophobias high frequency is due to birth trauma, about which he says is "one of the most horrendous experiences we can have during our lifetime", and it is in this helpless moment that the infant develops claustrophobia. Magnetic resonance imaging (MRI) can trigger claustrophobia. An MRI scan entails lying still for some time in a narrow tube. In a study involving claustrophobia and MRI, it was reported that 13% of patients experienced a panic attack during the procedure. The procedure has been linked not only to the triggering of preexisting claustrophobia, but also to the onset of the condition in some people. Panic attacks experienced during the procedure can stop the person from adjusting to the situation, thereby perpetuating the fear. S.J. Rachman tells of an extreme example, citing the experience of 21 miners.