Added detail: Krauthammer is Canadian -- most (not all) Canadians are extremely Liberal. Krauthammer is also Jewish -- most (not all) Jews support the Democrats. Krauthammer is disabled -- many (not all) disabled people like the Americans with Disabilities Act(very big government) and hold out hope for Embryonic Stem Cell research. And, as you point out, he is a psychiatrist. I've known quite a few of those, and every single one has been a Liberal.
I simply don't trust Krauthammer anymore. I hear him talking lately and I can't help thinking "That's a Liberal position he's advocating."
Krauthammer worked for Carter and wrote for The New Republic and was a speech writer for Mondale. I’d say if he is not a liberal he certainly leans that direction.