Internalizing problems can differ in boys and girls since early childhood: findings from the Child Behavioral Checklist 1.5-5

Objective: Internalizing problems disproportionately affect females in adolescence and adulthood, but research at earlier ages is limited due to a focus on disruptive behaviors. Our study addresses this gap by exploring the structure of internalizing problems and gender differences in Brazilian preschoolers. Methods: We analyzed data from the Child Behavioral Checklist 1.5-5 (CBCL 1.5-5) as administered in the Preschool Mental Health Study (PreK Survey), involving 1,292 children aged 4 to 5 in Embu das Artes, state of São Paulo, Brazil. Confirmatory factor analysis and comparisons of means explored internalizing problems and gender variations. Results: A two-factor model best fit both internalizing and externalizing problems. A hierarchical model with four factors (emotionally reactive, anxiety/depression, somatic complaints, and withdrawn) best fit internalizing problems, achieving partial invariance between boys and girls. Boys scored higher in the withdrawn syndrome, while girls scored higher in the somatic complaint syndrome. Conclusion: Preschoolers’ internalizing problems warrant attention beyond their link to externalizing problems. While the overall construct is similar in boys and girls, divergent syndrome scores indicate potential distinct risk patterns requiring further exploration.