I love the insanity of the piece, the dark figure picking on her shoulder and which I guess is the source of her madness? The metaphore is really nice as you have objectified the fear that is sometimes the root-cause of such an illness. The balance then also of the dark shape of against the light background and the angle on which he sits is also very nice because it gives depth to the image almost as if it was painted in a 3 point perspective. I just now also noticed the embrella or whatever it is he is holding, covering her in darkness. Also a very strong metaphore. Severly cool. Additionally I really like the maddening charecter. At first I thought it was a little, almost dragonesk, charected as the tie looked like a tongue coming out of a white mouth. Then I noticed that it was a tie and then I saw the charecter as you've intended. Yet I kept falling back to my view of him which is cool because then he is sort of a man and a monster at the same time. Very nice.
Overall execution, well of course the woman could have been painted more realistically (Motivation for 4.5/5), but I am not sure that would have suited the painting as it is more about the fear and madness itself rather than her and the demon on her shoulder sort of speak. I did however mention the perspective and wished the whole piece had been like that, i.e. stretched up towards the left corner. However, that is more my subjective view than anything else :) Otherwise I can't really critique it, its a very nice image that will look great on your wall.
Great work :)