OBJECTIVES: Childhood mental illness (MI) has been steadily increasing in the U.S. The development of MI can be impacted by a number of social determinants including peer-group, familial, community, and income-based factors, in addition to comorbidity. This study investigated the rate of MI in a sample of U.S. youths to examine the relationship between socioeconomic status and MI.

METHODS: This retrospective analysis utilized the IBM^® MarketScan^® Research Databases spanning 2012-2018. Annual samples of youths aged 4-17 continuously enrolled for the stated year and year prior were defined in the Commercial and Medicaid databases; prevalence rates of MI were calculated. Children with a diagnosis code for alcohol/substance abuse, depression, anxiety, eating disorders, bipolar, schizophrenia, developmental disorders, or attention/conduct disorders were classified as having a MI; rates were compared between commercially insured and Medicaid youths.

RESULTS: From 2013 to 2018, prevalence rates of mental illness were consistently higher for Medicaid compared to commercially insured youths; the gap in diagnosis decreased from 92.9% in 2013 (22.3% vs. 11.6%) to 44.2% in 2018 (20.8% vs. 14.4%). Among commercially insured youths, the prevalence rate of any MI increased 24.7%, while Medicaid youths evidenced a slight decrease (-5.5%). For specific diagnoses, rates of anxiety increased 38.5% and 67.9% for Medicaid and commercial groups respectively, while substance abuse rates declined for both (-41.0% vs. -20.4%). Depression, attention/conduct, and developmental disorders were elevated and stable over time in Medicaid youths, while commercial youths evidenced increases.

CONCLUSIONS: Medicaid coverage was associated with an increased likelihood of MI in youths, though rates are increasing among the commercially insured. Although income level and disability continue to be associated with severe MI, the increased rates of MIs among the commercially insured suggest a number of non-material determinants are also significant factors in the mental well-being of US youths, and warrant further investigation.