A new study links ADHD and conduct disorder in young adolescents with increased alcohol and tobacco use. The Cincinnati Children's Hospital Medical Center study is among the first to assess such an association in this age group.

Conduct disorder is a behavioral and emotional disorder marked by aggressive, destructive or deceitful behavior.

The study is published in the journal Drug and Alcohol Dependence.

"Early onset of substance abuse is a significant public health concern," says William Brinkman, MD, a pediatrician at Cincinnati Children's Hospital Medical Center and the study's lead author. "Adolescents who use substances before the mid-teen years are more likely to develop dependence on them than those who start later. This is why prevention is so important."

Dr. Brinkman and his colleagues studied data on more than 2,500 teens between the ages of 12 and 15. The data came from the 2000-2004 National Health and Nutrition Examination Survey (NHANES), which is a nationally representative sample of the United State population designed to collect information about health.

Teens with a diagnosis of ADHD and conduct disorder had a three- to five-times increased likelihood of using tobacco and alcohol and initiated use at a younger age than those who had neither disorder. Having ADHD alone was associated with an increased likelihood of tobacco use but not alcohol use.