Hello. I am trying to google this but I cannot find a specific answer, but I am fairly sure that it exists. 

The mental disorder results in the person acting as if they are on a television show; as if a crowd is always watching. This person does not LITERALLY think people are actually watching them, but their interpersonal interactions take place as if they did. 

For example, lying about something to the only other person who was involved in said event, who cannot possibly be lied to. 

For another example, putting on an intense and long-lasting act with very theatrical behavior during arguments, such as exaggerated posture to show dismissal of other person or refusing to look at said other party despite being asked to time and time again. 

It's hard to list all the specific symptoms because there are so, so many that take place that all individually may look like some other mental illness or not even a mental illness at all. 

To summate: the person regularly behaves as if they are being watched and have something to prove and some reason to show off and act hard and tough and uncaring, even when no such audience exists. This person does not literally believe that there is anyone watching them.