I usually say, "I am a certified nut ball" or something like that. This only happens with friends if they see that I am going through something. For work and non-friends I will usually excuse myself and tell them I am going theough something when I act a fool, I really try to control myself in public. My occupation alloows for me to be able to hide it.

With family and friends I say, "I'm bipolar" which pretty much means give me some space when I am mixed, or this is what is going on with me when I am manic or empty (I have heard this is the depressive part, except I do not consider myself as a person that ever gets depressed, just meh and empty.)