Attention deficit hyperactivity disorder in first- and second-generation immigrant children and adolescents : A nationwide cohort study in Sweden

Background: Studies on the incidence of Attention Deficit Hyperactivity Disorder (ADHD) among immigrant children and adolescents is limited and results are mixed. The aim of this study was to compare the ADHD risk between first- and second-generation immigrants aged 4–16 years and their native peers in Sweden. Methods: This was an open nationwide retrospective cohort study. We included 1,902,526 native and 805,450 children and adolescents with an immigrant background, born 1987–2010, and aged 4–16 years at baseline. We identified participants using national population data and participants were observed until they received an ADHD diagnosis in the National Patient Register, turned 18 years, migrated, died, or until the end of the study, whichever came first. ADHD risks were adjusted for birth year and age and maternal income at baseline. Results: For both males and females, the ADHD risk was lower among most immigrant groups. However, the combination of a Swedish-born mother and foreign-born father was associated with an increased risk of ADHD. The ADHD risk varied substantially between immigrants from different regions of the world. For example, immigrants from other Scandinavian countries, North America, and Latin America and the Caribbean had higher rates of ADHD compared with natives. Conclusions: Future research should examine the underlying factors behind the differences in ADHD risks between certain immigrant subgroups and natives, such as family structure, cultural and language barriers and potential differences in health care utilization among immigrant families