Claustrophobia can be regarded as a disability. If you look at the meaning of disability, according to Google, disability means a mental condition that limits a person's movement, sense and activities. This simply means anything related to mental condition that stops you from performing optimally is a disability.
A person suffering from claustrophobia, which is an anxiety disorder which usually results to irrational or intense fear towards a confined or enclosed spaces. With the definition of claustrophobia, it means those people who are claustrophobic cannot work in an enclosed place, thereby making them disables. The condition is an anxiety disorder, and anxiety disorder is a form of mental disorder.
Which means if a mad person is called a disable, it means those who are claustrophobic are also disabled, disabled from working optimally in an enclosed place. The United States law on American Disability Act (ADA) is very clear on this.