Executive functions in preschool children with externalizing behavior problems: a meta-analysis.

Deficits in executive functions (EF) have been found in school-age children and adolescents with externalizing behavior disorders. Present meta-analysis was carried out to determine whether these EF impairments can also be found in preschool children with externalizing behavior problems. Twenty-two studies were included with a total of 4021 children. Four separate meta-analyses were conducted, concerning overall EF, working memory, inhibition and cognitive flexibility. A medium correlation effect size was obtained for overall EF (ESzr = 0.22) and for inhibition (0.24), whereas a small effect size was found for working memory (0.17) and for cognitive flexibility (0.13). Moderator analyses revealed a stronger effect for older preschoolers compared to younger preschoolers, and for children from referred samples compared to community samples. These results show that EF, especially inhibition, is related to externalizing behavior problems already in preschool years.