BACKGROUND: Although the role of diet is increasingly acknowledged in psychiatry, data are still scarce regarding its early impact on the most significant behavioral disorders of childhood (i.e., hyperactivity-inattention and conduct problems). OBJECTIVES: The objective of this study was to explore the relation between children's dietary patterns at 2 years and developmental trajectories of hyperactivity-inattention and conduct problems between 3 and 8 years. METHODS: We recruited 1432 mother-child dyads from the French EDEN (etude sur les déterminants pré- et postnatals du développement et de la santé de l'enfant) mother-child cohort to conduct the analyses. Three dietary patterns, labeled guidelines, processed and fast foods, and baby foods, were identified using an FFQ in children aged 2 years in a previous study. The Strengths and Difficulties Questionnaire was used to assess hyperactivity-inattention and conduct problems at 3, 5, and 8 years of age and build related trajectories from 3 to 8 years. The relation between children's dietary patterns at 2 years and the worst developmental trajectories of hyperactivity-inattention and conduct problems were determined with multivariable logistic regressions adjusted for potential socioeconomic, maternal, and child confounders. RESULTS: The score on the guidelines dietary pattern was negatively associated with the risk of hyperactivity-inattention problems (OR: 0.75; 95% CI: 0.60-0.94), contrary to adherence to the baby foods dietary pattern (OR: 1.41; 95% CI: 1.16-1.71). CONCLUSIONS: Distinct patterns of children's diet at 2 years were predictive of developmental trajectories of hyperactivity-inattention problems between 3 and 8 years. These results highlight the relevance of conducting further studies to clarify the mechanisms involved.< Réduire