Among young adolescents, aggression is linked to a likelihood of experimenting with cigarettes or marijuana for the first time, while impulsivity confers a greater risk of trying alcohol, a new study shows.

However, the researchers found no association between attention-deficit/hyperactivity disorder (ADHD) and substance-use initiation.

Dr. Monique Ernst of the National Institute of Mental Health in Bethesda, Maryland and her colleagues sought to determine whether a psychiatric diagnosis like ADHD or behavioral measures such as level of aggression or impulsivity might influence the risk that a child would try pot, cigarettes or alcohol for the first time. They followed 78 12- to 14-year-old boys and girls, 50 of whom had been diagnosed with ADHD.

Four years after the study had begun, 37 of the participants had not tried substances, 41 had tried at least one, and 29 had experimented with more than one. Just three cases could be defined as substance abuse, as opposed to substance use.

Kids who used tobacco were more aggressive and hyperactive and had more trouble with attention and learning than nonsmokers, the researchers report in the medical journal Pediatrics. Statistical analysis found that a child’s level of aggressiveness was independently tied to tobacco use. Aggression also independently predicted marijuana use.

The only characteristic associated with trying alcohol was impulsivity. This suggests, the investigators note, that there may be different biological factors that make a person vulnerable to starting to use a particular substance.

The researchers also found that aggressive teens were more likely to use substances heavily and to try more substances.

However, Ernst and her colleagues found that children with ADHD, ADHD plus conduct disorder, depression or anxiety were no more likely to try substances than their peers without a psychiatric diagnosis. The team suggests that it may make more sense to identify at-risk teens by looking at the severity of certain behavioral symptoms, rather than any particular psychiatric diagnosis.

“Substance-use initiation confers vulnerability for later substance abuse, and a better understanding of its behavioral predictors can help to shape preventive measures at both the individual and societal levels,” they conclude.

SOURCE: Pediatrics, June 2006.