When you talk about a country you never visited, consider Paris syndrome
en.wikipedia.org
en.wikipedia.org
Perhaps in some it's even triggered because of the trip, as disruptions from normal routines and environs can be such a trigger, but a dozen or two out of millions doesn't rise above the (much higher) baseline of mental healh issues present in the population.
(Given about 33 million tourists per year and the approximate rate of 1:1600 baseline of psychosis in the population, more than 20,000 tourists might be expected to suffer from such a condition. That a handful have an episode on vacation is not evidence of some special syndrome)
https://www.sbs.com.au/news/paris-syndrome-culture-shock-sic...