What do you suggest for a depressed, fearful cat?

[Jilly_in_VA]

We have a cat in the stray jail at the shelter who is scared and depressed. She's been there a week and only seems to come out of her feral den to use her litter box when no one is around. She's not eating and is drinking very little. The background is this--she is apparently a feral cat who was caught in a trap by someone a week ago and was in the trap overnight, where she beat up her face quite badly trying to get out. Since she came to us in strays, she just sits in her feral den with the window open and either sleeps or stares blankly out of it, refusing to interact at all. We've tried tempting her with toys, treats, catnip, and the best wet food we can find, to no avail. We're all worried about her. Anyone have any ideas?