Great Movies w/ Singular Character in Solitary Despair?

Maybe a better question would be, “Is there a movie like ‘Hunger’”?
He’s in every scene. The people he meets along the way aren’t important, and take up no more than a few seconds. He’s a writer who can’t eat because he can’t write. He can’t write because he doesn’t eat. The little money he makes, he gives away. He’s in a battle with himself.

I think because the character from Knut Hamsun’s “Sult” is so rare also helps this 10/10… Per Oscarsson is also one hell of an actor who could be so convincing in Danish or English (Peckinpah’s “Wine Noon”)

https://youtu.be/RShayOfGTJ8

Polanki’s character in “The Tenant”.

EDIT: would Isabelle Adjani in “The Story of Adele H” count?

Couple more:
“Bring Me the Head of Alfredo Garcia”
“Eraserhead”
“PeepingTom”

The one that springs to mind is The Revenant.

There are two ordeals going on: one for the main character and the other for the audience. That film is brutal.

You know, I remember the actress only, but not the movie. Saw it years ago. I saw the others, and think “Peeping Tom” is an excellent movie that also fits excellently. Every time I think of that movie, “The Collector” (1965) comes to mind for some reason. He obviously wasn’t alone the entire movie, but he is in his own world.

Not clear on the parameters of the question. Works about alienated individuals? Plenty of those:

Silent Snow, Secret Snow, by Conrad Aiken. Paul’s Case by Willa Cather (which in no small way inspired Catcher in the Rye). Spider, a typically creepy David Cronenberg, Herman Hesse’s Steppenwolf, Edith Wharton’s House of Mirth (where the line between alienation and desperation is blurred). And of course Poe, Kafka, Celine and Beckett are chock full of it.

Catherine Deneuve in “Repulsion” came to mind (although she interacts with some other characters).

Crossed my mind too.
(and really - not sure how many films there are with a lone protagonist interacting with next to no people, as the OP seems to be looking for)

(heh - “Castaway”? Never saw the film, so don’t know how much “despair” Tom’s character was going through)

David Thewlis’ character in Naked, directed by Mike Leigh.

A butt ton of despair; great contribution.

Last year’s The End We Start From features (an excellent) Jody Comer alone during a catastrophic storm in London. To be fair, she is with her newborn, but the baby doesn’t have any dialogue.
I suppose an obvious one is Vincent Price in The Last Man on Earth, unless the OP is looking form films literally featuring one person.

Just saw it. The island scenes, which are a lot of the film, are pretty despairing.

“Leaving Las Vegas”. Elisabeth Shue’s character is fleshed out quite a bit, but Nicolas Cage’s anguish is the main feature here.

A Man Escaped (1956) and Pickpocket (1959) would seem to qualify, probably along with other Robert Bresson films I haven’t seen because they looked too slow and/or boring.

Johnny Got His Gun.

Great movies

Great movie. I think it’s still on YouTube for free.

Very good movie. Although the owner seemed even more deranged!

Robert Redford in All Is Lost, Ryan Reynolds in Buried and Tom Hanks in Cast Away?

The very first card in “Le Samourai” says, “There is no greater solitude than that of the samurai unless it is that of the tiger in the jungle… Perhaps…” However Samurai do not feel despair…

On which note, I Am Legend must surely count, especially the scene with Will Smith talking to the mannequin after he puts down his dog.

It wasn’t a Great Movie (I can’t even remember the name), but it was one guy, driving and talking on a cell phone. His whole life kinda unravels over the course of him driving to attend the birth of his child with some woman he cheated on his wife with. Loses his family, job, the works.

It was a tedious film.