As EPT/ELBW children reach school age, it is important to identify the types of behavior and social impairments they have at school entry. Evaluations conducted during the kindergarten year in school indicated that the EPT/ELBW group had higher rates of ADHD and deficits in social functioning at school than NBW classmates. Approximately twice as many EPT/ELBW children compared with NBW controls met criteria for diagnoses of ADHD Hyperactive-Impulsive (28% vs. 13%) and ADHD Combined (33% vs. 16%) on a structured psychiatric interview. Teacher ratings in the clinical range on the ADHD Inattentive scale were nearly five times higher in the EPT/ELBW group (19% vs. 4%). The rates of these disorders are comparable to those reported in other studies.15
The EPT/ELBW group also had higher rates of problems in behavioral organization and self-monitoring (i.e., metacognition). Group differences in rates of disorders in metacognition and social functioning remained significant when excluding children with neurosensory disorders or a deficit in global cognitive ability, indicating increased risks for these disorders even among EPT/ELBW children without pervasive impairment.
The EPT/ELBW group had more psychiatric symptoms and higher ratings of behavior or social problems on scales that failed to reveal group differences in rates of disorder. Specifically, the EPT/ELBW group had more parent-reported symptoms of ADHD-Inattentive, Oppositional Defiant Disorder, and enuresis and higher teacher ratings of emotional disturbance, problems in behavior self-control, and defiant/disruptive behaviors. These results confirm both internalizing and externalizing behavior problems in this population. Dimensional differences on several measures of behavior problems, metacognition, and social functioning remained significant when excluding children with neurosensory disorders or a deficit in global cognitive ability. The results are consistent with other evidence for subclinical elevations in behavior and social problems in EPT/ELBW children.3,4,9,43
The types of behavior and social disorders found in this sample have been identified in previous research on EPT/ELBW children conducted at early school age.14–16
The present study demonstrates that these disorders continue to be evident even in children born in the early 2000s, a period during which rates of neurodevelopmental impairment have declined.44
Past studies document similar disorders in both younger and older preterm children,4,6,7,10–13,22,24,45
suggesting that behavior problems emerge early in childhood and persist over time. The EPT/ELBW group’s higher rate of ADHD Inattentive but not ADHD Hyperactive/Impulsive or Oppositional Defiant Problems on the TRF is also consistent with past observations of more problems in attention than in hyperactivity or externalizing behaviors, especially on teacher reports.3–7,9,22–24
In addition, however, the EPT/ELBW group had a higher rate of ADHD Hyperactive-Impulsive on the P-ChIPS, higher symptom counts for Oppositional Defiant Disorder on the P-ChIPS, and higher teacher ratings of Defiant/Disruptive problems. The results accord with those of Samara et al.15
in documenting a wide range of behavior problems in EPT/ELBW children at early school age.
Many of the group differences remained significant when considering only EPT/ELBW children in regular classrooms, providing new evidence that even those EPT/ELBW children attending regular classes have more behavior problems than their classmates. In comparisons restricted to the subset of children in regular classrooms with both parent and teacher ratings, higher rates of behavior problems were more evident on the teacher ratings. Specifically, on rating scales with comparable parent/teacher forms (CBCL vs. TRF, BRIEF-parent vs. BRIEF-teacher), inattentiveness and problems in behavioral self-regulation were more often identified by teachers. The results suggest that teacher ratings, while generally consistent with those by parents, may be more likely to identify disorders in these areas at school entry and support efforts to obtain reports from both sources.
As observed in previous research, behavior problems were more prevalent in boys than in girls and in children with lower vs. higher SES.7,9,46
Contrary to some previous investigations,9,15
we did not find that the effects of extreme prematurity on behavior were more pronounced for boys than girls. The lack of a moderating effect of sex on group differences was unexpected given evidence for a greater vulnerability of males to complications of preterm birth and early childhood neurodevelopmental impairment,47
though other studies have reported similar findings.7,22,24
Performance of EPT/ELBW children on tests of executive function was related to diagnoses of ADHD Inattentive, ADHD Combined, and Enuresis as well as to behavioral indications of executive dysfunction. Contrary to several past studies,14,15,18,22–24
lower global cognitive ability was not associated with behavior or social problems in this EPT/ELBW cohort. This pattern of results suggests that executive function skills are more closely related to attention disorders in EPT/ELBW children than is overall intelligence.3
Recent findings showing that deficits on tests of executive function are associated with ratings of inattentive and overactive/impulsive behaviors in older preterm children support this interpretation.23
Deficits in executive function skills have been identified in children with a wide range of clinical conditions and are viewed by many as being integral components of ADHD.48–51
Associations of tests of executive function with enuresis suggest that weaknesses in executive function either contribute directly to lack of bladder control or signal abnormalities in brain regions underlying this disorder.
To our knowledge this is the first study to document behavior and social outcomes of extreme prematurity in a sample of EPT/ELBW children all of whom were enrolled in kindergarten at the time of assessment. The data provide information on the likelihood of clinically relevant levels of behavior and social problems in our sample relative to base rates for peers from similar sociodemographic backgrounds. This study is also one of few to assess behavior self-regulation and social functioning at school, use a formal psychiatric interview to assess behavior outcomes,9
and investigate performance on tests of executive function in relation to behavior outcomes in young EPT/ELBW children. One advantage of using a structured psychiatric interview is that questioning is focused on behaviors that are relevant to diagnostic criteria. A further benefit is that the interview format helps to ensure parent understanding of questions and provides opportunities to clarify parent responses. The utility of the P-ChIPS was demonstrated in this study by its sensitivity to group differences in rates of ADHD diagnoses and the relation of these diagnoses to deficits on tests of executive function.
One of the study’s limitations is that we were unable to recruit 25% of the surviving birth cohort of EPT/ELBW children treated at a single perinatal center. The absence of differences in background and neonatal status of the participants and non-participants suggests that the sample was representative of our regional population. However, behavior outcomes in our largely urban sample may not be representative of outcomes in other regions. Another concern is that the examiners who administered the P-ChIPS were not blind as to birth status. The P-ChIPS is a highly structured interview, syndromes identified on interview were related to corresponding DSM-Oriented syndromes obtained from parent ratings of behavior, and inter-rater reliability for scoring of parent responses was high. Nevertheless, we cannot rule out the possibility that examiner bias contributed to group differences. A further limitation was the failure to include a measure of autism spectrum disorders, especially in view of recent findings suggesting increased symptoms of autism in EPT/ELBW children.3,4,22
Teacher ratings confirm elevated rates of social deficits in the EPT/ELBW group. Although social deficits are also associated with ADHD and deficits in executive function,52,53
it is unclear how many children met criteria for autism.
In summary, the results confirm adverse behavior and social consequences of extreme prematurity at school entry. These consequences are evident both at home and at school and include increased rates of ADHD, impaired social functioning, and poor self-control. The high rates of these disorders in kindergarten underscores the importance of screening EPT/ELBW children for behavior problems when they first enter school if not before.54
Recognition of these disorders at school entry would assist parents and teachers in setting realistic expectations for the child and facilitate more timely behavior interventions. Early interventions are likely to be more effective than later ones and may mitigate the negative effects of behavior and social problems in kindergarten on children’s subsequent academic learning.25,26
The findings also demonstrate associations of tests of executive function with disorders in attention and self-regulation in EPT/ELBW children. These associations demonstrate the utility of neuropsychological assessments in identifying children at risk for behavior disorders. Ongoing follow-up of our sample will help establish the stability of children’s behavior disorders and their relation to subsequent academic progress. Based on previous findings we anticipate that attention disorders in kindergarten will forecast later problems in reading and mathematics.55
Further efforts will be required to examine even earlier manifestations of behavior problems in this population and to design follow-up programs that help to insure that these problems are recognized as soon as they become evident and provide for continuity of care from birth through school age. A system of care such as a “medical home” would serve this purpose56
and neuropsychological follow-up would be useful in tracking development. Additional research is also needed to examine biological and environmental risk factors, explore the neural basis of these problems and other developmental antecedents (e.g., social cognition and communication skills), and test behavior interventions.