More than 20 years ago, E. Jane Costello, Ph.D., and collaborators at Duke University Medical Center initiated what has since proven to be one of the most illuminating studies ever undertaken in the field of epidemiology―the branch of medicine that seeks to describe and explain the prevalence of various illnesses in specific subsets of the general population.
The study, called the Great Smoky Mountains Study, had the straightforward aim of determining precisely how commonplace anxiety disorders are during childhood and adolescence. To accomplish this, Dr. Costello, a 2007 NARSAD Distinguished Investigator Grantee, and colleagues, including her husband, Adrian Angold, M.D., in 1993 recruited 1,420 children, then aged 9, 11 and 13. A large portion of these young people, drawn from 11 rural counties in western North Carolina, were followed through age 26. Some are still being followed. When the study began, some experts still believed that childhood psychiatric disorders were quite rare. The Great Smoky Mountains Study clearly demonstrated that this was certainly not true for anxiety disorders. For this achievement, Drs. Costello and Angold were awarded the Foundation’s 2009 Ruane Prize for Outstanding Achievement in Child and Adolescent Psychiatric Research.
In the most recent discoveries based on the massive Smoky Mountain dataset, published January 1st in Child & Adolescent Psychiatry, Drs. Costello, Angold and colleagues, including William Copeland, Ph.D., a 2008 NARSAD Young Investigator Grantee, report that within any three-month period throughout the years of childhood, 13.3 percent of the children in the study meet the criteria for a diagnosable psychiatric disorder. Most valuable has been the ability of the team to make cumulative assessments, over many years, of the prevalence of psychiatric problems of all kinds. This showed that by the age of 21, over 61 percent of the children in the study had met the criteria for at least one disorder. An additional 21 percent reported “subclinical” symptoms. “This brought the cumulative psychiatric burden to 82.5 percent,” Dr. Costello and colleagues note.
“Although mental illness is commonly perceived as being uncommon or even rare, this suggests most young adults have experienced such illness at some period in their development,” the researchers say. The newest data further indicate that anxiety is a “common mental health issue to have had by adulthood, and much more common than has previously been suggested,” they report. All childhood anxiety disorders were associated with poor health in young adulthood. Generalized anxiety disorder in childhood correlated strongly with higher adult risk of depression. The researchers found that the transition from adolescence to adulthood is particularly fraught with risk for anxiety, and propose that additional research try to pin down what in the transition specifically accounts for this.