[Prevalence of psychiatric and substance use disorders among three generations of migrants: Results from French population cohort].

INTRODUCTION: Mental health of migrant populations has become a major public health issue since these populations more often suffer from mental health problems than host populations. The influence of the migration process on the emergence of these disorders and its impact on future generations is uncertain. This study provides an estimate of the prevalence of mental disorders among three generations of migration.

METHOD: The study was conducted in the general population by the French Collaborating Center of the World Health Organization, in France, on a sample of 37,063 people aged 18 and older. The subjects interviewed were selected by a quota sampling method and, thus, were representative of the general population in the 47 study sites in France. This method develops a sample of subjects with the same characteristics as the general population on predefined issues, such as age, sex, educational level and socioprofessional category. The designation of migrant status was based on the country of birth of the subject, the subject's parents and the subject's grandparents. We defined a migrant as first generation (a subject born abroad; n=1911), second generation (at least one parent born abroad; n=4147), or third generation (at least one grandparent born abroad; n=3763) of migrants. The diagnostic tool used was the Mini International Neuropsychiatric Interview (MINI). The MINI is a brief structured diagnostic interview developed by psychiatrists for ICD-10 and DSM-IVTR psychiatric disorders in the general population. The comparisons by generation of migrants were performed by chi-square test for qualitative variables and by an analysis of variance for quantitative variables. The same tests were used to compare the presence of mental disorders according to the characteristics of the population. Factors with a P-value less than 0.2 were entered in a multivariable logistic regression to assess the relationship between the generation of migrants and the presence of mental disorders, adjusting for the confounding factors.

RESULTS: Thirty-eight per cent of migrant subjects have psychological difficulties, versus 30 % in the host population. These results are observed on three successive generations of migrants. Migration status increases risk of depressive disorders (OR=1.555), bipolar disorder (OR=1.597, CI=1.146-2.227), post-traumatic stress disorder (OR=1.615), substance abuse (OR=2.522) and alcohol abuse (OR=1.524), and drug dependence (OR=2.116). This risk is maintained at the second and third generation. The migration process affects mental health of population regardless of socioeconomic status or geographic origin.

CONCLUSION: The consideration of migration and generation of migration shows a specific psychopathological risk profile. This is related to the joint action of a migratory past and precarious socioeconomic situation.