Objective To investigate the mental health of children and adolescents admitted to neonatal intensive/special care units (NICUs) in infancy.

Methods This cross-sectional study used a provincially representative cohort from the 2014 Ontario Child Health Study. Parents provided data on psychiatric disorders using the MINI International Neuropsychiatric Interview for Children and Adolescents in 3141 children aged 4–11 years (NICU n=389; control n=2752) and in 2379 children aged 12–17 years (NICU n=298; control n=2081). Additionally, 2235 adolescents aged 12–17 years completed the interview themselves (NICU n=285; control n=1950). Odds of psychiatric disorder were compared in those admitted and controls.

Results Based on parent reports, NICU graduates aged 4–11 years had increased adjusted ORs (95% CI) of 1.78 (1.39 to 2.28) for any psychiatric disorder, with a marginal prevalence of 32.4% in NICU participants and 27.6% in controls. At this age, NICU graduates also had increased ORs of 1.74 (1.25 to 2.40) for psychiatric comorbidity, 1.48 (1.04 to 2.11) for oppositional defiant disorder, 1.61 (1.19 to 2.19) for attention-deficit hyperactivity disorder, 4.11 (2.33 to 7.25) for separation anxiety disorder and 2.13 (1.37 to 3.31) for specific phobia. At 12–17 years, 40.5% and 30.5% of NICU graduates and 30.6% and 17.9% of controls had any psychiatric disorder as reported by parents and self-report, respectively. Parents and adolescents, respectively, reported increased adjusted ORs (95% CI) of 1.63 (1.18 to 2.26) and 1.55 (1.13 to 2.11) for any disorder, 1.64 (1.06 to 2.54) and 1.74 (1.11 to 2.73) for psychiatric comorbidity, and 1.89 (1.22 to 2.93) and 3.17 (2.03 to 4.95) for oppositional defiant disorder.

Conclusions NICU graduates are at increased risk for psychiatric disorders during childhood and adolescence.