Patrick Jane, has been known to have a past where he went mental, I believe that he was once Red John. However after becoming so upset with killing his wife and daughter he has lost control over his own sense. His mind has taken over and he went crazy,as seen in flashbacks of season 1. As you see in corner of the wall there is a red John face perfectly drawn. I believe that his mind took over his body and he became self obsessed with Red John. As Patrick Jane is a con artist I think that Jane has conned himself.
