So what happens to Carol after the movie? (I.e. is anyone optimistic?)
Over the years, this board has been filled with debate over the film's message, but there's been no single thread where anyone has debated Carol's fate. Seems like everyone thinks she gets worse at the clinic, not better, and will probably die there from malnutrition and increasing isolation. Either she'll be a complete shut-in like the mysterious figure in a protective suit, or she'll die in the igloo like the man who lived there before her.
One of those is probably the likely, if cynical, outcome, based on what Haynes intended to convey. But to me the clinic is a lot more ambiguous, and she really does improve there in some facets. She is calmer, more at peace. If nothing else, she is surrounded by people who, at least on the surface, are sympathetic and understanding of her illness, even if it's really just depression and anxiety and they are only making her worse by feeding into her delusions.
Whether or not (her) environmental illness is real, there is something to be said for Haynes's depiction of the physical space of the clinic compared to the suburban life Carol left behind. In her Los Angeles house and in her day-to-day chores and activities, Carol was physically dwarfed by materialism and visual clutter around her. In contrast, the natural landscapes of New Mexico offer her a sparse, unadulterated scenic beauty that she couln't find in L.A. And in the igloo, for the first time she appears not to be visually overwhelmed by her surroundings. The downside is that it's a blank space; it ultimately gives her life no more purpose than decorating her mansion ever did.
In the end she is able to look at herself in the mirror and say she loves herself. Other posters here seem to think she is robotically reciting these words without really feeling them, and that at the clinic she is as disconnected from her true self as she ever was.
It's a bleak, ambiguous ending, to be sure. Carol reminds me of anorexics or other types of addicts who make gradual progress in rehab centers. There they have doctors and sponsors to monitor their activities and provide them support, but they are unable to readjust to the real world -- if they ever even reenter it.
Of course, the harsher comparison to be made is to a cult. Even this theory I find ambiguous though. For example, by telling the residents that they are responsible for their own illnesses, is the leader encouraging the sort of unhealthy victim-blaming that will keep people from having the courage to leave? Or is he trying to help them realize that their physical conditions are partly the result of their mental conditions, and thus they are ultimately in control over their own bodies? One thing's for sure -- no one seems to be leaving that clinic except in a body bag.
The retreat is sort of a self-imposed insane asylum for Carol. Surrounded by others who feed into her environmental paranoia, she withdraws further inward, becomes even quieter and incoherent in conversation, and carries her oxygen tank with her everywere. But does she at least seem more at peace, or is it just me? Is it more like she has already suffered such a psychotic/emotional break that, untreated, she is gradually withering away?