Close, but the most depressing movie was “Graveyard of the Fireflies” a Japanese animated film. The only reason more people don’t kill themselves after watching it is because they’re too depressed.
Oddly enough I found Nevil Shute’s “On the Beach” surprisingly hopeful despite the fact that nobody was going to escape death.
I guess the fact that they tried living or at least died on their own terms in the face of hopelessness made it seem hopeful to me.
Yes, depressing but it was designed to touch the soul, so to speak. I’ve never seen a sadder ending....