Children born extremely preterm (EP; <26-week gestation) are 3–4 times more likely to develop psychiatric morbidities in middle childhood, the most common of which is ADHD. The aim of this study was to evaluate the prevalence of ADHD symptoms in EP children at age 11 and assess whether particular symptom domains are associated with early childhood behavioural and cognitive characteristics.
Participants were EP babies born in the UK and Ireland from March–December 1995 (N=811). All surviving children were subject to follow-up assessments at age 2 (n=283), 6 (n=241) and 11 (n=219) (alongside matched, term-born controls at age 6 and 11). Assessments at 2 and 6 years of age included evaluation of cognitive, motor, behavioural, neurodevelopmental and neuropsychological outcomes. The primary outcome examined at age 11 was the manifestation of ADHD symptoms evaluated by parents and teachers based on the DuPaul ADHD Rating Scale IV.
When considering children with both parent and teacher evaluations, results show that presentation of both inattention symptoms (mean* score difference 1.2 standard deviations [SD]; 95% confidence interval [CI] 0.9–1.5; p<0.001) and hyperactivity/impulsivity symptoms (mean score difference 0.5 SD; 95% CI 0.2–0.7; p<0.01) was more frequent in EP children at age 11 compared with term-born controls, with a more important effect size for the former. Predictors of inattention at 11 years included outcomes such as smaller head circumference, internalising behavioural problems, lower psychomotor development index by age 2, lower intelligence quotient scores and pervasive peer relationship problems by age 6. In contrast, significant independent predictors of hyperactivity/impulsivity included lower IQ, pervasive conduct problems and ADHD symptoms at 6 years, externalising problems at 2.5 years, and non-white maternal ethnicity.
The authors concluded that EP children are at higher risk of developing ADHD with predominant inattention symptoms by age 11. Inattention and hyperactivity/impulsivity symptoms were associated with distinct sets of early neurodevelopmental, cognitive and behavioural indicators.
Read more about predictors of ADHD in EP children at age 11 here
*Combined parent and teacher
Johnson S, Kochhar P, Hennessy E, et al. Antecedents of attention-deficit/hyperactivity disorder symptoms in children born extremely preterm. J Dev Behav Pediatr 2016; 37: 285-297.