Since coming to Emory in 1991, Waldman has focused his research on the classification and causes of childhood disruptive behavior problems such as ADHD, which affects 3 percent to 5 percent of the child population. Children with ADHD typically have moderate to severe problems in paying attention, controlling impulses and maintaining normal activity levels. They often make rash judgments and have problems both in school and in their relationships with peers. ADHD typically occurs more frequently in males than in females, which suggests that some of the causes of the disorder may be gender-specific.
Also included within the group of childhood disruptive behavior disorders are conduct disorder, oppositional defiant disorder, and problems of aggression and antisocial behavior. Previous research has shown that a sizable proportion of children who are diagnosed with ADHD also tend to exhibit aggression and antisocial behavior. Although many studies have documented this overlap, the reasons for it remain unknown. Consequently, Waldman is conducting a number of studies that should help to illuminate the causes underlying the overlap among these behavior problems. One such project involves studying a large number of identical and fraternal twin children.
"Twin studies can shed special light on the causes underlying personality and behavior," Waldman explained, "because comparisons of the similarity of identical and fraternal twins can help disentangle genetic and environmental influences."
Waldman was granted access by the Georgia Department of Vital Records and Health Statistics to the birth records of all twins born in the state from 1973 to 1991. So far, Waldman and his research assistants have gathered demographic information on about 1,200 twin pairs aged 4-15 and their families. This summer, Waldman will begin a mail questionnaire study of behavior problems and personality in these twins.
"The study, supported by a National Institute of Mental Health B-START grant, should help discern the genetic and environmental influences predisposing to childhood disruptive behavior problems and their overlap," said Waldman.
In a separate yet related project, Waldman is collaborating on a study examining the relation of specific DNA markers to childhood disruptive behavior problems. He hopes the results of these studies will increase understanding of the causes that predispose children to develop these disorders and that such understanding will lead to their eventual prevention.