I don't think that's a factor. The ISS is anything but lonely. Astronauts have internet up there and are regularly in touch with their family. I think it's also reasonable to say they know what they're getting into when they go up, so physical separation is unlikely to affect astronauts as badly as the general population. Many of these people are ex-military and have regularly been on long deployments away from home.
I'll have to disagree based on my reading of Endurance by Scott Kelly. It is more the profound isolation away from everyone on earth, not the lack of communication. He struggled with saying goodbye to everyone who came up to the station with him, as he watched the missions rotate. It becomes different when you're doing a whole year vs 3-6 months.