The researchers said depression, anxiety, substance abuse and conduct disorders can have dire consequences, such as dropping out of school, arrests and convictions, teen pregnancy and suicide attempts.
The Duke University Medical Center study of more than 1,400 families also found that only one in five children with these disturbances received help for their condition.
The findings of the four-year study are published in the May issue of the American Journal of Public Health. The project was funded by the National Institute of Mental Health and is expected to follow these 9-, 11- and 13-year-old children until they are 22 years old.
Duke psychologist Jane Costello, lead author of the study, said the findings should ultimately help professionals identify children and adolescents at risk for emotional disturbances by predicting the risk factors that contribute to their development.
"We know the risk factors for heart disease, diabetes and other chronic illnesses, but we know much less about how mental health problems develop," Costello said. "You can't prevent emotional disturbances until you know what the early warning signs are."
In the study, researchers wanted to determine how many children suffer from various emotional disturbances, what factors cause them, how many kids get help and what barriers exist to getting help. Researchers selected the Great Smoky Mountains region because of its well-developed mental health care system, figuring that a good system would better reflect persistent and widespread problems common to all systems.
One of the major findings was that poverty put white children at risk for emotional disturbance but had little effect on American Indian children. This was the case despite the fact that Indians had a much higher poverty rate than whites: one-fourth of the white children were poor, whereas two-thirds of the Indian children were poor.
Costello theorizes that widespread poverty may have a less harmful effect on certain populations where it is a socially accepted norm.
"There may be an attitude that, we're all poor, so there's no stigma attached to it and therefore less stress associated with it,'" she said. The stress of poverty, racism, and type-A personalities has been linked to increased risk of heart disease and early death in adults, according to Duke studies conducted by Dr. Redford Williams.
The study showed that poverty had no effect on children's physical health. The height, weight and general health status of poor children were equivalent to those of middle-class kids, and the poor children had no higher incidence of infectious diseases.
On the issue of access to mental health care, researchers found that only one in five rural children with emotional disturbance received help for their condition, a ratio similar to that found in major cities. In Pittsburgh, for example, Costello found that only one in seven children received appropriate mental health care.
Of the children who received help in the North Carolina study, 75 percent of them received it through school counselors. The remaining 25 percent sought help mainly through the professional mental health system, including psychiatrists, psychologists and social workers in the community.
"That finding concerned us, because if families aren't able to get mental health services in an area where good resources exist, what does that say about regions where mental health care is scarce or hard to access?"
When they looked at why kids weren't getting help, researchers received surprising answers from parents. The top reason parents listed was the fear of losing their child to the state or of losing parental rights, a fear that Costello said is generally unfounded, since a main goal of mental health and child welfare services is to keep families together.
The study found other barriers to care were lack of information, cost factors, lack of time, and the shame and stigma associated with mental illness.
Researchers had expected cost to be a bigger factor in blocking access, Costello said. But the study showed that children with private insurance were no more likely to get mental health care than kids with no insurance. Children with Medicaid were twice as likely to get mental health care, possibly because they were identified through government social service agencies.
Costello said that cost was important in relation to its burden on the family and society as a whole. Having a child with a serious emotional disturbance is costly to the family because many parents cannot work with a sick child or must go on welfare to cope financially. Costello said the cost to society is both a social and financial burden.
"By the age of 16, kids with serious emotional disturbance are four times more likely to have been convicted of a crime," she said. "These kids are going to be a major economic burden on the state. If we could identify them early and treat them, we could reduce that burden dramatically."
By following the entire study cohort of 1,420 families until the children are 22, researchers said they hope to see if any new mental health patterns emerge, how well children make the transition from childhood mental health care to adult mental health care, and whether the researchers were able to predict which children would be at risk for serious mental disorders in adulthood.