Prevalence of serious mental disorder in 7000 refugees resettled in western countries: a systematic review.

BACKGROUND: About 13 million people are classified as refugees worldwide, and many more former refugees have been granted citizenship in their new countries. However, the prevalence of post-traumatic stress disorder, major depression, or psychotic illnesses in these individuals is not known. We did a systematic review of surveys about these disorders in general refugee populations in western countries.
METHODS: We searched for psychiatric surveys that were based on interviews of unselected refugee populations and that included current diagnoses of post-traumatic stress disorder, major depression, psychotic illnesses, or generalised anxiety disorder. We did computer-assisted searches, scanned reference lists, searched journals, and corresponded with authors to determine prevalence rates of these mental disorders and to explore potential sources of heterogeneity, such as diagnostic criteria, sampling methods, and other characteristics.
FINDINGS: 20 eligible surveys provided results for 6743 adult refugees from seven countries, with substantial variation in assessment and sampling methods. In the larger studies, 9% (99% CI 8-10%) were diagnosed with post-traumatic stress disorder and 5% (4-6%) with major depression, with evidence of much psychiatric comorbidity. Five surveys of 260 refugee children from three countries yielded a prevalence of 11% (7-17%) for post-traumatic stress disorder. Larger and more rigorous surveys reported lower prevalence rates than did studies with less optimum designs, but heterogeneity persisted even in findings from the larger studies.
INTERPRETATION: Refugees resettled in western countries could be about ten times more likely to have post-traumatic stress disorder than age-matched general populations in those countries. Worldwide, tens of thousands of refugees and former refugees resettled in western countries probably have post-traumatic stress disorder.