"Estranged" may me sufficient in the context you describe. Merriam Webster gives this as the second definition of estranged.
2 : to remove from customary environment or associations "The first words spoken were not those of one becoming estranged from this world, and already permitted to stray at times into realms foreign to the living."— Charlotte Brontë
I think of Mersault as estranged in Camus's The Stranger. "Meursault is psychologically detached from the world around him. Events that would be very significant for most people, such as a marriage proposal or a parent’s death, do not matter to him, at least not on a sentimental level. He simply does not care that his mother is dead, or that Marie loves him."
And the mood established in the Door's song "When You're a Stranger," is estrangement: Lyric: "People look ugly when you're alone."