Mood disorders and migration: meta-analysis.

BACKGROUND

Migration is a risk factor for the development of schizophrenia.

AIMS: To examine whether migration is also a risk factor for bipolar affective disorder, unipolar depressive disorder and mood disorders in general.

METHOD: Medline was searched for population-based incidence studies concerning mood disorders among migrants and mean relative risks were computed using a mixed-effects statistical model.

RESULTS

Only a few studies of unipolar depressive disorder were retrieved. The mean relative risk of developing bipolar affective disorder among migrants was 2.47 (95% CI 1.33-4.59). However, after excluding people of African-Caribbean origin in the UK this risk was no longer significantly increased. The mean relative risk of mood disorders of unspecified polarity was 1.25 (95% CI 1.04-1.49) and that of any mood disorder was 1.38 (95% CI 1.17-1.62).

CONCLUSIONS

There is no conclusive evidence for a large increase in the risk of mood disorders associated with migration.