Is he he faking or is he really crazy?

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I have a student of mine who seems to act very normal but as soon as he finds something, according to him, a little out of the ordinary starts acting a fool. He starts screaming loud and hitting the walls with his face and hands. But twenty minutes later he could be perfectly normal. What is going on? Is he faking? I cant give his initials . He would probably read this and use this as an excuse to go off.