Abstract
BACKGROUND: Internal migration is a special case in Germany, with its history of two formerly divided and re-unified states. In this study, we examined mental health of women and men who migrated internally after the German reunification and compared them with each other and with the non-migrated population in Eastern and Western Germany. METHODS: Baseline data of 161,795 participants (49.9 % women; internal migrants East-West = 7160 [4.4 %] and West-East = 3966 [2.5 %]) from the population-based German National Cohort were used. Internal migration was measured using information on previous (1988) and current residency. To assess mental health (i.e., current depression and anxiety symptoms), the Depression Module of the Patient Health Questionnaire (PHQ-9) and the Generalised Anxiety Disorder Symptoms Scale (GAD-7) were applied. Group differences were assessed using analyses of covariance and Tukey's Tests. Strengths of effects were tested using omega squared. RESULTS: Significant differences in levels of current depression and anxiety symptoms between the four groups were found for both women and men, but effect sizes were extremely small (ω² ≈ 0.000-0.002). East-West migrants reported slightly lower current depression symptoms (adj. M (women) = 4.00, adj. M (men) = 3.17) than West-East migrants (adj. M (women) = 4.48, adj. M (men) = 3.69). For East-West migrated men the same was found for anxiety symptoms (adj. M = 2.52 versus adj. M = 2.96). Mental health of internal migrants was not better compared to their non-migrated counterparts. CONCLUSION: Subgroup analyses revealed group differences to depend on sex, but show negligible effect sizes, with internal migration only explaining less than 0.2 % of the variance for depression and anxiety symptoms. Internal migration alone is thus no substantial factor in explaining mental health differences. Future studies should use longitudinal data to determine temporal associations between internal migration and mental health.