Black and Hispanic children are half as likely to be diagnosed with ADHD when compared to their white peers, according to a new study by researchers Pennsylvania State University.

"We're seeing that the disparities occur as early as kindergarten and then remain and continue until the end of eighth grade," lead researcher Paul Morgan told Reuters.

The likely reason, Morgan explains, isn't due to actual fewer instances of ADHD, but rather a prevalence of underdiagnosis for minority children, which means many children who could benefit from treatment - whether it be medication, talk therapy or extra help in the classroom - may be missing out.

In all, the researchers tracked 15,100 kids from the kindergarten class of 1998-1999 via regular parent surveys.

At each survey point, which included kindergarten, first, third, fifth and eighth grades, white children were most likely to have ADHD. All races followed a similar trend, however, with new diagnoses peaking around third grade.

This peaked by the spring of eighth grade at which 7 percent of white children had received an ADHD diagnosis, according to parents, compared to 3 percent of black children and just over 4 percent of Hispanic youth.

Another possibility is that white children are over-diagnosed; however, the study cannot say either way.

Whichever is true, reports Dr. Tanya Froehlich, an ADHD research at Cincinnati Children's Hospital Medical Center, cultural backgrounds appear to be playing a role.

"There just seems to be more wariness and concern in African American groups," both about being diagnosed with ADHD and the medications used to treat the condition, she told Reuters.

In another conversation with HealthDay, however, Froelich also pointed to another likely influencer: health insurance.

Sure enough, the study showed that children without health insurance were less likely to be diagnosed with ADHD than children who were covered.

The consequences of untreated ADHD, Froelich warned, can be extensive.

"We know that people with ADHD have higher rates of failing a grade in school, lower academic achievement, lower achievement in their jobs, higher rates of incarceration, higher rates of substance abuse, more problems with relationships, and higher rates of depression and anxiety," Froehlich told HealthDay.

Recently, the Centers for Disease Control and Prevention (CDC) announced that one in five children between ages 3 and 17 have a mental health disorder and, based on their research, ADHD appears to be the most prevalent.

For this reason, officials at the agency explained, they are working to increase access and quality of care for not only those with ADHD, but all mental health disorders. 

"Millions of children in the U.S. have mental disorders that affect their overall health and present challenges for their loved ones. In addition, the financial costs of childhood mental disorders are at least an estimated $247 billion each year," Dr. Tom Frieden, director of the CDC, said in a news release. "We are working to both increase our understanding of these disorders, and help scale up programs and strategies to promote children's mental health so that our children grow to lead productive, healthy lives."