THE INFLAMMATORY-IMMUNE AXIS AND THE DEVELOPMENT OF PSYCHIATRIC DISORDERS IN CHILDHOOD: TRANSLATIONAL AND CLINICAL EVIDENCE

Abstract

Introduction: Recent evidence suggests that inflammatory and immunological processes play a relevant role in the development of psychiatric disorders from early stages of life, influencing neurodevelopmental trajectories and mental health in childhood and adolescence. Prenatal immune activation, as well as persistent inflammatory states throughout growth, have been associated with different psychiatric outcomes, including mood disorders, psychosis, attention deficit hyperactivity disorder, and autism spectrum disorders. Objective: To synthesize current clinical and translational evidence on the relationship between the inflammatory-immune axis and the development of psychiatric disorders in childhood and adolescence. Methodology: This is a structured literature review, based on articles published between 2020 and the present, identified in recognized scientific databases. Systematic reviews, meta-analyses, and prospective cohort studies that evaluated pediatric populations or prenatal exposures associated with psychiatric or neurodevelopmental outcomes were included. The selection of studies followed previously defined eligibility criteria, and the data were analyzed using narrative synthesis organized by thematic axes. Results and discussion: The analyzed studies demonstrated a consistent association between early inflammation and a higher risk of psychiatric disorders. Prenatal exposures, such as fever and maternal infections, were related to an increased risk of neurodevelopmental disorders. In childhood and adolescence, elevated levels of pro-inflammatory cytokines, especially interleukin 6, were associated with depression, psychosis, and ADHD, while persistent trajectories of low-grade inflammation increased the risk of mental disorders in adulthood. Children with immune-mediated diseases also presented a higher prevalence of psychiatric comorbidities, reinforcing the interaction between chronic inflammation and mental health. Conclusion: The body of evidence indicates that the inflammatory-immune axis acts as a transversal biological factor in the development of psychiatric disorders from childhood, influencing multiple psychopathological trajectories. Understanding these mechanisms broadens perspectives for prevention, early risk identification, and more integrated therapeutic approaches in child mental health.