Household income and first psychiatric hospital admissions among children and adolescents.

Background: Parental socioeconomic factors are associated with mental health outcomes already during childhood, but gender differences in these connections have rarely been studied.

Aims: We explored the associations between household income and severe mental health disorders requiring psychiatric inpatient hospital care, with particular focus on gender differences.

Methods: In this national register-based cohort study, we followed over 1.6 million children and adolescents born in Finland between 1991 and 2020 until first psychiatric hospital admission, moving away from parents, death, emigration from Finland or the end of 2020, whichever time came first. We calculated age- and gender-specific incidence rates (IRs) for first admissions. In order to evaluate gender differences and the magnitude of association between income and psychiatric hospital admission, we fitted multivariable Poisson regression models and calculated incidence rate ratios (IRRs) and 95% confidence intervals.

Results: In total, 2.1% of the study population were admitted to psychiatric hospital for the first time within the specified period. Among girls in all income deciles, IRs distinctly peaked during adolescence. Among boys, IRs started to increase earlier, especially in the lowest income deciles, and there was no steep peak during adolescence in any income group. Lower household income was associated with higher risk for psychiatric hospital admission, and this association was steeper for boys (IRR 3.18 [2.87-3.53] than for girls (IRR 2.15 [1.97-2.35]) in the lowest compared to the highest income decile, after adjusting for potential confounders.

Conclusion: Our results indicate that low income may play a more prominent role in severe mental disorders among boys, whereas adolescence emerges as a critical period for girls, regardless of their household income levels.