MONDAY, Feb. 7 (HealthDay News) -- Two-thirds of American children with attention-deficit/hyperactivity disorder struggle with other mental health and developmental conditions, such as learning disabilities and anxiety, a new study suggests.
Examining data on nearly 62,000 children aged 6 to 17 obtained from the 2007 National Survey of Children's Health, researchers found that those with ADHD had higher odds than others of repeating a grade at school and dealing with strained social and family relationships.
Notably, children from poor families were nearly four times as likely as affluent children to suffer from multiple conditions associated with ADHD, which also include conduct disorder, depression and speech problems, among others, the study said.
"This is a really striking finding that I don't think has been documented before," said study author Kandyce Larson, a research associate at the Center for Healthier Children, Families & Communities at the University of California, Los Angeles.
ADHD, a condition characterized by impulsiveness and difficulty staying focused, is one of the most common cognitive and behavioral disorders diagnosed in school-age children, according to the study reported online Feb. 7 in the journal Pediatrics. It affects about 8 percent of U.S. children, the study authors noted.
The data analyzed by Larson and her team used detailed parent interviews to learn if a health-care provider had ever told them their child had ADHD. An "Aggravation in Parenting" scale measured parental stress by asking how often the child angered them and if the child was much more difficult to care for than others.
In total, 67 percent of youngsters with ADHD had at least one other reported mental health or neurodevelopmental disorder, compared with 11 percent of unaffected American children. Eighteen percent had three or more additional conditions, the study authors said.
Richard Milich, a professor of psychology at the University of Kentucky, praised the study for its large sample population but pointed out that all the data came from parental reporting, which he considers a limitation.
"Is this reality or parental perception? A dysfunctional mother may find a child multiply impaired because she may not be able to handle it," said Milich, who has studied ADHD for 35 years.
Milich noted that low-income children tend to have risk factors, such as suboptimal nutrition, that may explain why they struggle disproportionately with other conditions associated with ADHD.
"I'm not especially surprised that the more comorbidities they have, the worse the outcome is," he said. "It's extremely rare to see a kid with ADHD and nothing else."
While the study didn't address treatment interventions for ADHD-affected children, Larson said it suggests a large group is "slipping between the cracks of care."
"This really suggests we need to be doing more, to have more proactive treatment strategies and support for families," she said. "Treatment does need to be more individually tailored . . . and the findings show a need for greater integration of services between health, mental health and social services across sectors."
The U.S. National Institute of Mental Health has more information about ADHD.