I know from hearsay and can sympathize from my own experience that many people experience depression overseas when learning a language fully immersed. I can imagine that this leads to low-confidence and self-doubt which could lead to how decisions are made and the world perceived. Yet, on the other hand, many bloggers and language learners praise full immersion as the best way to go without really mentioning the potential psychological toll it takes to be an adult and not be able to, say, politely excuse oneself for the washroom.
Is there any research about the negative psychological effects of immersion to learn languages?