Emotion Regulation Difficulties as a Developmental Pathway Linking Early-Life Gut Microbiota Composition to Subsequent Problematic Behaviors: A Longitudinal Study

Problematic behaviors during childhood are associated with an increased risk of later mental health difficulties. Emerging evidence suggests that the gut microbiota may contribute to behavioral problems by influencing the development of executive function (EF), particularly explicit emotion regulation (EER). This longitudinal study investigated whether gut microbiota composition was associated with the risk of problematic behaviors. We analyzed data from 68 typically developing children assessed at both 3 and 5 years of age. Gut microbiota composition and EF, including EER, were assessed at ages 3 and 5 using 16S rRNA gene sequencing and the Behavior Rating Inventory of Executive Function–Preschool Version, respectively. The risk of problematic behaviors was assessed at age 5 using the Child Behavior Checklist. A higher relative abundance of Coprobacillus at age 3 was associated with poorer EER at age 3, which was prospectively associated with an increased risk of both externalizing (indirect effect = 0.29, 95% CI [0.01, 1.04]) and internalizing behavioral problems (indirect effect = 0.28, 95% CI [0.01, 0.87]) at age 5. In addition, a lower relative abundance of Granulicatella at age 5 was associated with poorer EER at age 5, which mediated the association with internalizing behavioral problems at age 5 (indirect effects = −0.35 and −0.36; 95% CIs [−1.32, −0.07] and [−1.18, −0.05], respectively). These findings provide evidence that gut microbiota composition may represent an early indicator of subsequent mental health risk. However, given the sample size and the number of taxa examined, these findings should be regarded as exploratory.