I'm sure there's vast statistical data and psychological analysis regarding the relationship between mood and music, but I'm not convinced any "number" or "evaluation" can really come close to indicating the role music plays in living. Music is like commercials, pretty hard to avoid - But it's so much more than that.
Sometimes I catch myself humming, randomly [and in inappropriate situations] without even realizing it at first [thus catch..taking no responsibility for the action itself] or dancing to the beat in my head. No, I don't have a condition. I feel it - as I'm sure other people do. Music is an almost inescapable part of us. It's tied to our culture and history; experiences and memories (good and not so much); everyday activities.
The soundtracks of our lives are spotted with melody; Can you hear it?