Abstract
Migration is now well understood to be associated with mental illness in many parts of the world. However, the cause and effects of migration that are associated with mental illness continue to be a point of debate. The Ethnic Density concepts give a plausible explanation. On further elaboration, we conclude that a move from a sociocentric society to an egocentric one leads to more distress and more mental illness. Cultural incongruity faced by a migrant in an alien culture has a similar impact. Several theories on migratory distress have tried to explain psychiatric morbidity: high morbidity at source, individual predisposition, stress, misdiagnosis and racial discrimination. We hypothesise that the impact of ethnic density and cultural congruity occurs in a social context.