Children who are diagnosed with attention deficit hyperactivity disorder at an early age are at greater risk of depression and suicide than other teens and parents need to take the condition seriously, U.S. researchers said on Monday.

They said 18 percent of children in a study who were diagnosed with ADHD between ages 4 to 6 were depressed as adolescents - about 10 times higher than adolescents without ADHD.

And about 5 percent of children with an early ADHD diagnosis thought about committing suicide at least once, and were twice as likely as other children to have tried it.

“This is another pretty powerful demonstration that parents should not disregard ADHD in early childhood,” said Benjamin Lahey of the University of Chicago, who worked on the study published in the Archives of General Psychiatry.

ADHD is one of the most common child mental disorders and is estimated to affect around 3 percent to 5 percent of children globally.

Children with ADHD are excessively restless, impulsive and easily distracted, and often have difficulties at home and in school. There is no cure, but the symptoms can be kept in check by a combination of medication and behavioral therapy.

For the study, researchers from the University of Chicago and the University of Pittsburgh in Pennsylvania, followed 123 children diagnosed with ADHD at age 4 to 6 for up to 14 years, until they reached 18 to 20.

They compared these children with 119 children from similar neighborhoods and schools. The children were checked every year for the first four years, then during years 6 through 9 and 12 through 14.

“This is a study that ... shows that children diagnosed at 4 to 6 years of age are at increased risk for depression and to some extent suicide during late childhood and adolescence,” Lahey said in a telephone interview.

The researchers did not study children diagnosed at an older age.

Lahey said suicide attempts were relatively rare, noting that more than 80 percent of children with ADHD did not try to commit suicide and no one in this study committed suicide.

SOMETHING TO TAKE SERIOUSLY

Even so, the disease is something to take seriously.

“We’ve known for a long time that children with ADHD are at risk for all kinds of problems such as accidental injuries,” Lahey said. Children with ADHD are also more likely than others to smoke and abuse drugs.

“At least some segments of the public tend to regard ADHD as something too minor to take seriously. There is a sense to some that it is psychiatriaztion of normal exuberance,” he said.

Last week, British researchers discovered the first direct evidence that ADHD is a genetic disorder, a finding they said should help dispel the myths that ADHD is caused by bad parenting or high-sugar diets.

“I think the best advice we can give is that they take it seriously and seek help from a mental health professional early on so they can help the child have the best possible outcome.”

Millions of people take ADHD drugs including Ritalin, Concerta, Adderall, Vyvanse and Strattera. Global sales of ADHD drugs were estimated at around $4 billion dollars in 2009.

SOURCE:  Archives of General Psychiatry, October 2010.