It is also confused sometimes with Cleithrophobia (the fear of being trapped).Diagnosis of claustrophobia usually transpires from a consultation about other anxiety-related conditions. Certain criteria have to be met to be diagnosed with specific phobias. This criteria includes:
an interminable obstructive or excessive fear caused by the existence or anticipation of a specific situation
anxiety response when stimulus is exhibited; can result in panic attacks in adults or, for children, an outburst, clinging, crying, etc. acknowledgment by adult patients that their fear stems from the anticipated threat or danger
engaging in procedures to evade dreaded object or situation, or proneness to face the situation but with discomfort or anxiety
the persons evasion of the object or situation impedes with everyday life and relationships
the phobia is continuous, usually for 6 months or longer
symptoms cannot be ascribed to other underlying mental conditions, such as obsessive-compulsive disorder (OCD) or post-traumatic stress disorder (PTSD)

Scale
This method was developed in 1979 by interpreting the files of patients diagnosed with claustrophobia and by reading various scientific articles about the diagnosis of the disorder. Once an initial scale was developed, it was tested and sharpened by several experts in the field. Today, it consists of 20 questions that determine anxiety levels and desire to avoid certain situations. Several studies have proved this scale to be effective in claustrophobia diagnosis. Questionnaire
This method was developed by Rachman and Taylor, two experts in the field, in 1993. This method is effective in distinguishing symptoms stemming from fear of suffocation.
These reactions constitute an autonomic failure in a panic attack. 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 claustrophobic people, this translates as panicking or overreacting to a situation in which the person finds themselves physically confined. Classical conditioning
Claustrophobia 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 individuals life. Such an experience can occur multiple times, or only once, to make a permanent impression on the mind. The majority of claustrophobic 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, claustrophobia seems to be the result of past experiences. Conditioning experiences
A few examples of common experiences that could result in the onset of claustrophobia 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.