In the last chapter of Open Wounds Maedhros refuses to eat. Was it because he had lost his appetite or was he deliberately denying himself food despite being hungry?
Hmm, I think he was probably on a pendulum swinging between the two scenarios you describe. In the last chapter we see a bit of a regression in the healing process, a worrying 'wobble' in his mental health as he is more cognisant of the trauma he has been through. I think it quite natural therefore that someone going through a lot of mental anguish would lose their appetite - it is common when we are stressed or very anxious.
But I think there was also a self-destructive element in there too - in that last chapter in particular, Maedhros struggles to come to terms with the things that were done to him, and the things that he was forced to do to others during his captivity. Let's not mince words - he hates himself for it. Feeling simultaneously like a victim of abuse, and a perpetrator of it upon others, is excruciating for him mentally. And a part of that self-hatred comes out in how he interacts with others; becoming withdrawn or sullen, feeling unworthy of attention or comfort, denying himself food, etc.
So indeed I think that both drivers of the behaviour were at play here - both in physical loss of appetite due to stress, and the self-destructive little hook that kept on digging at him.
