Hi there my son who is staying with us sometimes have terriable mood swings, he will walk into the house all friendly go to his room and all of a sudden when he comes out he is agressive and very rude without any reason, he also go out sometimes without telling us where he is going and only get home in the early hours and when we ask him about it he shouts at me and his dad, we were just wondering if he might have bipolar disorder, or split personality, what do you think?