Background: Mental health problems in preschool children are rising in Sweden, yet their economic impact on the health sector remains poorly quantified. This study estimated the incremental healthcare utilization and costs associated with early mental health problems to inform resource allocation and early intervention.

Methods: We analyzed an exact matched sample of 1206 drawn from a cohort of 6957 children aged 3-5 from Uppsala Region, Sweden. Early mental health problems were identified using the Strengths and Difficulties Questionnaire reported by mothers, fathers and teachers. Data were linked to national registers to estimate cumulative healthcare utilization and costs over four years from a health sector perspective. Hurdle models, generalized linear models, and two-part models compared utilization and costs between children with and without early symptoms. Sub-group analyses by sex, symptoms, and raters were performed.

Results: Children with early mental health problems consumed three additional units of medication with an incremental cost of US$ 299, one additional specialized outpatient visit with an incremental cost of US$ 622, and five additional primary care visits with an incremental cost of US$ 376 compared to their healthy peers. Healthcare utilization and costs were higher for boys with externalizing and internalizing symptoms. Findings were consistent across all rater groups.

Conclusions: Early childhood mental health problems represent a substantial economic impact to the healthcare sector. The findings suggest that early identification and intervention in the preschool years may offer significant opportunities for cost-offsetting and improved long-term system efficiency.