The fear of enclosed spaces is an irrational fear. Most<unk>  people who find themselves in a room without windows consciously know that they are not in danger, yet these same people will be afraid, possibly terrified to the point of incapacitation, and many do not know why. Amygdala The red structure is the amygdala. The amygdala is one of the smallest structures in the brain, but also one of the most powerful. The amygdala is needed for the conditioning of fear, or the creation of a fight-or-flight response. A fight-or-flight response is created when a stimulus is associated with a grievous situation. Cheng believes that a phobia's roots are in this fight-or-flight response. In generating a fight-or-flight response, the amygdala acts in the following way: The amygdala's anterior nuclei associated with fear each other. Nuclei send out impulses to other nuclei, which influence respiratory rate, physical arousal, the release of adrenaline, blood pressure, heart rate, behavioral fear response, and defensive responses, which may include freezing up. These reactions constitute an 'autonomic failure' in a panic attack. Brain synapse A study done by Fumi Hayano found that the right amygdala was smaller in patients who suffered from panic disorders. The reduction of size occurred in a structure known as the corticomedial nuclear group which the CE nucleus belongs to. This causes interference, which in turn causes abnormal reactions to aversive stimuli in those with panic disorders. In<unk>  people, this translates as panicking or overreacting to a situation in which the person finds themselves physically confined. Classical conditioning<unk>  results as the mind comes to connect confinement with danger. It often comes as a consequence of a traumatic childhood experience, although the onset can come at any point in an individual's life. Such an experience can occur multiple times, or only once, to make a permanent impression on the mind. The majority of<unk>  participants in an experiment done by Lars-Göran Öst reported that their phobia had been "acquired as a result of a conditioning experience." In most cases,<unk>  seems to be the result of past experiences. Conditioning experiences A few examples of common experiences that could result in the onset of<unk>  in children (or adults) are as follows: *A child (or, less commonly, an adult) is shut into a pitch-black room and cannot find the door or the light-switch. *A child gets shut into a box. *A child is locked in a closet. *A child falls into a deep pool and cannot swim. *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 parent's 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. Speyrer's<unk>  and the Fear of Death and Dying", the reader is brought to the conclusion that<unk> 's 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<unk> . In an MRI, the patient is inserted into the tube. Magnetic resonance imaging (MRI) can trigger<unk> . An MRI scan entails lying still for some time in a narrow tube. In a study involving<unk>  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'<unk> , 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. The conditions inside a mine S.J. Rachman tells of an extreme example, citing the experience of 21 miners. These miners were trapped underground for 14 days, during which six of the miners died of suffocation. After their rescue, ten of the miners were studied for ten years. All but one were greatly affected by the experience, and six developed phobias to "confining or limiting situations". The only miner who did not develop any noticeable symptoms was the one who acted as leader. Another factor that could cause the onset of<unk>  is "information received." As Aureau Walding states in "Causes of<unk> ", many people, especially children, learn who and what to fear by watching parents or peers. This method does not only apply to observing a teacher, but also observing victims. Vicarious classical conditioning also includes when a person sees another person exposed directly to an especially unpleasant situation. This would be analogous to observing someone getting stuck in a tight space, suffocated, or any of the other examples that were listed above. Prepared phobia There is research that suggests that<unk>  isn't entirely a classically conditioned or learned phobia. It is not necessarily an inborn fear, but it is very likely what is called a prepared phobia. As Erin Gersley says in "Phobias: Causes and Treatments", humans are genetically predisposed to become afraid of things that are dangerous to them.<unk>  may fall under this category because of its "wide distribution… early onset and seeming easy acquisition, and its non-cognitive features." The acquisition of<unk>  may be part of a vestigial evolutionary survival mechanism, a dormant fear of entrapment and/or suffocation that was once important for the survival of humanity and could be easily awakened at any time. Hostile environments in the past would have made this kind of pre-programmed fear necessary, and so the human mind developed the capacity for "efficient fear conditioning to certain classes of dangerous stimuli". Rachman provides an argument for this theory in his article: "Phobias". He agrees with the statement that phobias generally concern objects that constitute a direct threat to human survival, and that many of these phobias are quickly acquired because of an "inherited biological preparedness". This brings about a prepared phobia, which is not quite innate, but is widely and easily learned. As Rachman explains in the article: "The main features of prepared phobias are that they are very easily acquired, selective, stable, biologically significant, and probably non-cognitive." 'Selective' and 'biologically significant' mean that they only relate to things that directly threaten the health, safety, or survival of an individual. 'Non-cognitive' suggests that these fears are acquired unconsciously. Both factors point to the theory that<unk>  is a prepared phobia that is already pre-programmed into the mind of a human being.
Claustrophobia
Phobia
Hyperreligiosity
Body integrity dysphoria
Alexithymia
Emotional lability
Automatism 
Automatic behavior