The mental health of migrants is affected by many factors that stem from premigratory experiences as well as adaptation conditions of the host nation. The interaction of these two types of factors are however set in time: certain periods are characterized by relative stability, while others are marked by unexpected disruptions which tend to make migration appear as a never‑ending process. An individual's age upon arrival in a new country is also an important factor: adolescents must meet many different types of demands, while the elderly no longer have the personal resources to assimilate a new culture. The author points out that adaptation takes place in a family system where the fortune of each member impacts on that of others in the family. In this article, the author discusses prevention by taking into consideration certain issues raised by scientific literature.