Their findings indicate that disparities in ADHD diagnosis begin to occur early in children's school careers.
"Whether these disparities extend to Hispanic children has also been unclear. We find that their initially observed disparities are related to non-English language use in the home."
Analyses of kindergarten teacher-reported classroom behaviour indicated that neither black nor Hispanic children displayed less frequent ADHD-related behaviours than white children, suggesting that a lower incidence of ADHD symptomology did not explain minority children's comparatively lower rates of diagnosis.
"One explanation for our findings is that black parents may be relatively more reluctant to obtain a mental health diagnosis for their children, while language barriers may explain Hispanic children's lower likelihood of diagnosis," Morgan said.
"It may also be the case that pediatricians and other professionals are not soliciting developmental concerns as often from minority families."
A lack of treatment for ADHD may result in some minority children experiencing more learning and behavioral problems as they start school, so that they quickly begin falling behind their peers.
"One practical application is that these groups of children may have unmet treatment needs," Morgan said.
"Pediatricians, psychiatrists and school-based practitioners should be sensitive to the possibility that cultural and linguistic barriers are resulting in systematic under-diagnosis for some groups of children."
"Ensuring minority children are appropriately diagnosed and treated for ADHD may require overcoming these barriers."
Providing minority parents with information on recognizing potential ADHD symptoms in their children, as well as encouraging help-seeking behaviours when meeting with professionals, may also help prevent or reduce racial/ethnic diagnosis disparities.
"I hope that our findings inform efforts to help all children with ADHD," Morgan said. "If untreated, ADHD can very quickly begin to interfere with children's opportunities for school success."
More information: "Racial/ethnic disparities in ADHD diagnosis by kindergarten entry." Morgan PL, Hillemeier MM, Farkas G, Maczuga S. J Child Psychol Psychiatry. 2014 Jan 24. DOI: 10.1111/jcpp.12204. [Epub ahead of print]