Mental Disorders within a Legal Case

Last week for my activity I watched the movie I am Sam.  One of the witnesses for the defendant, Sam, is his neighbor Annie.  Annie is an agoraphobic who makes the trip to the courthouse with great difficulty.  The movie is of course a drama and this event added to the drama but it caused me to think about that type of situation.  I wonder how attorneys question witnesses who are agoraphobics or shut-ins.  However difficult that may have been in the past, it is now easy with our current technology.  One could easily set up a video chat with the person and question in the courtroom while the person stays within their home.  But that resolution only pertains to agoraphobics, it might not work with people who have paranoid personality disorder.  People who have certain mental disorders have been discredited for years.  While they may have a disorder having to do with one aspect of their life, it does not mean they can not properly testify for the trial.  I found this article on mind.org which discusses this matter with more depth than I have, but describes these occurrences as discriminatory.  A person was quoted as saying, "If I'd had a broken leg or cancer this would not have been brought up to use against me..."  This entire site is dedicated to fighting for equality for people with mental disorders.  As psychologists, we could advocate for persons with mental disorders within a case.  This could be a case within itself to find a way to prove to the courts that a person is a credible source.  It seems as though this topic is an insanity plea in reverse, a plot not seen in movies.