Creating Art or Going Crazy

I had a professor at the School of Visual Arts who recounted a story that to me, has become kind of a litmus test for being an artist. It is simply this: if you walk away from your art completely and start to feel like you have an itch you need to scratch, or you feel kind of crazy and restless...doodling in the margins of you papers and such then you need to face up to the fact that you are an artist and do it. It has been like that for me. I do not know why a need to paint, I just do. I wonder if there is a word to describe this feeling. I would be interested in what others have to say.