culture shock

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A condition of confusion and anxiety affecting a person suddenly exposed to an alien culture or milieu.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun anthropology, sociology A state of anxious confusion experienced by someone exposed to an alien or unfamiliar environment.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a condition of disorientation affecting someone who is suddenly exposed to an unfamiliar culture or way of life or set of attitudes