Endotracheal Intubation in Early Life and Its Association with Mental Health Disorders from Childhood to Adolescence: A National Longitudinal Cohort Study up to Age 18

<b>Background/Objectives:</b> The long-term impact of intubation during infancy or early childhood on later childhood or adolescence remains unclear. This study investigates the association between early-life intubation and subsequent mental health outcomes. <b>Methods:</b> We conducted a retrospective cohort study using nationwide data on children born in Korea between 2002 and 2005. Those who underwent intubation (exposed cohort) were compared with 1:10 matched unexposed controls who did not undergo intubation. <b>Results:</b> The exposed cohort (<i>n</i> = 18,799) had a significantly higher incidence rate of mental health disorders than controls (28.2 vs. 13.9 per 1000 person-years; HR 1.82, 95% CI 1.74-1.93). Autism spectrum disorder (HR 3.09) and attention-deficit/hyperactivity disorder (HR 1.61) increased in early childhood, while bipolar disorders (HR 2.36), schizophrenia spectrum disorders (HR 2.27), depressive disorders (HR 1.94) and anxiety disorders (HR 1.84) increased in adolescence. Higher incidence was noted in females, children not admitted to intensive care units, and those without congenital heart disease or bronchopulmonary dysplasia (<i>p</i> < 0.05). Hospitalization length correlated with mental health outcomes (<i>p</i> < 0.001), but ventilator duration did not (<i>p</i> = 0.694). <b>Conclusions:</b> Early-life intubation is associated with an increased risk of mental health disorders, highlighting the need for long-term follow-up and support for these children. In particular, increased clinical awareness is needed during follow-up care for patients at higher risk, such as females, children without congenital heart disease or bronchopulmonary dysplasia, those intubated at an older age, and those with longer hospitalizations.