BALTIMORE – Persistent attention-deficit/hyperactivity disorder (ADHD) through young childhood is associated with both poorer academic outcomes and an increased risk of other mental health problems, according to a longitudinal study of younger children with ADHD.
An Australian study presented at the annual meeting of the Pediatric Academic Societies found that 67% of children who had ADHD at age 7 years still met the diagnostic criteria 3 years later, when they were 10 years old. Boys were more likely than girls to have retained the diagnosis (74% vs. 50%; odds ratio, 3.4; P = .01).
On average, children with ADHD had lower scores on math and reading tests than their matched peers without ADHD, even after adjustment for socioeconomic variables and comorbidities (mean difference, –7.6 for math and –8.7 for reading, P less than .001 for both).
When Emma Sciberras, Ph.D., and her colleagues examined the longitudinal data, they found that children who had a persistent ADHD diagnosis were more likely to have an externalizing disorder, such as a conduct disorder (57% vs. 33%; OR, 2.8; P = .008). They also were more likely to have a mood disorder (8% vs. 0%; P = .04).
No sex differences were seen, aside from the increased likelihood of a persistent diagnosis.
“Childhood ADHD confers risk for future mental health difficulties,” said Dr. Sciberras, a psychologist at Deakin University, Melbourne. Dr. Sciberras presented preliminary findings from the Children’s Attention Project, a 3-year study of 179 young children with ADHD and 212 children without the diagnosis.
The goal of the Children’s Attention Project, a community-based longitudinal study, was to document the natural history of ADHD. Aspects of the study included assessing the impact of ADHD on the mental health of both children and parents, as well as examining social, academic, and family functioning, and overall quality of life. The study also seeks to tease out both risks and protective factors that can tip outcomes toward the better – or worse – end of the spectrum, said Dr. Sciberras.
The Children’s Attention Project enrolled first graders from 43 primary schools in Melbourne, to compare 3-year outcomes of a sample of children with ADHD with a control group of children who did not have ADHD. In addition to assessing diagnostic stability (the persistence of an ADHD diagnosis), Dr. Sciberras and her collaborators also looked at functional outcomes. Sex differences in outcomes, as well as the effect of ADHD persistence, also were assessed for the community-based sample of children.
Children were enrolled after families and teachers of the first graders completed the Conners 3 ADHD Index. Families of children with positive screens and matched controls were offered enrollment in the study, with intake involving confirmation of the ADHD diagnosis, as well as detailed academic and behavioral assessments and a family survey. Children in the study were assessed at baseline, and then again at 18 and 36 months after enrollment. Longitudinal data were available for 72% of those initially enrolled.
Children in the study averaged 7.3 years old. Of the ADHD group, 124/179 (69%) were male, as were 135/212 (64%) of the control group. For children in the ADHD group, 31 (17%) had previously been diagnosed with ADHD, and 23 children (13%) were on ADHD medication at enrollment; none of the control group had a prior ADHD diagnosis or was taking medication. For 63 (38%) of the children in the ADHD group, their primary caregiver had not completed high school, compared with 39 (19%) in the control group.
“This is really more of a community-based approach to researching ADHD,” Dr. Sciberras said in an interview. Previous longitudinal studies, she said, had a near-exclusive focus on clinical samples, which can “overrepresent boys and children with more severe symptoms,” she said. Age ranges were broad, and follow-up was often infrequent. Most importantly, positive factors that lead to good outcomes for children with ADHD had been understudied, she said, and she and her colleagues are continuing to look for factors, such as resilience, that contribute to better social and emotional functioning.
It’s important to study children with ADHD in a real world manner because “childhood ADHD is associated with poorer academic outcomes, and the risk is evident from the second year of school,” said Dr. Sciberras. “We need to identify which factors lead to improved outcomes over time. The ultimate aim is to map functional impairment and key predictors from age 7 to later adolescence and adulthood.”
The study was funded by Australia’s National Health and Medical Research Council and by the Collier Foundation. Dr. Sciberras and her collaborators had no relevant financial disclosures.