Why do most psychologists believe that people suffering from conversion disorder invent physical symptoms?

People who have this disorder invent physical symptoms for them to gain freedom unbearable conflict.  Usually the physical symptoms of the syndrome affect the senses or movement. Common symptoms include blindness, partial or total paralysis, inability to speak, deafness, numbness, difficulty swallowing, incontinence, balance problems, seizures, tremors, and difficulty walking. 

These are the answer choices:

More natural disasters will occur.

Disease will spread more easily.

>Fewer shelters will be available.

New predators will move into the area.