Children showing oppositional behavior have a risk of addiction to cannabis, nicotine, and cocaine, while symptoms of inattention represent a specific additional risk of an addiction to nicotine. There seems to be no specific risks of substance abuse or dependence associated with hyperactivity. These finding came from a 15-year population-based study, by researchers at the University of Montreal, published in Molecular Psychiatry.

The behavior of 1,803 children between the ages of 6 and 12 was annually evaluated by their mothers and teachers - in order to explain the roles played by hyperactivity, inattention, opposition, anxiety, and adversity. More than half of the children were females.

The results showed:
  • 13.4% were either abusing or addicted to alcohol by age 21
  • 9.1% to cannabis by age 21
  • 2.0% to cocaine by age 21
  • 30.7% also had a problem with tobacco addiction
Scientists have already found the link between attention deficit hyperactivity disorder (ADHD) in childhood and substance abuse in adulthood. However, there has been very little research on the respective roles of behavioral symptoms, like opposition that are often concomitant with ADHD (without being part of the disorder), hyperactivity, and attention deficit. In order to assess the possible effect of gender on the findings, there were as many girls as boys sampled.

Dr. Jean-Baptiste Pingault, a postdoctoral fellow and first author of the study conducted under the supervision of Drs Sylvana Côté and Richard E. Tremblay, both researchers at the Sainte-Justine UHC's Research Center and professors at the University of Montreal, explained:

"By taking into account the unique effect of inattention and hyperactivity, which had seldom been considered separately before, we came to realize that the link between ADHD symptoms in childhood and substance abuse in adulthood was overestimated and hyperactivity in itself did not seem, in this study, to predispose for future substance abuse.

We have rather observed strong oppositional behaviors to be associated with cannabis and cocaine abuse. In ADHD symptoms, only inattention is closely correlated with nicotine addiction."

Observations showed that opposition and inattention play a largely identical role in girls and boys.

Drug Addiction and Oppositional Behavior in Childhood

Frequent oppositional behavior in childhood is the biggest behavioral predictor of substance abuse. Oppositional behavior can be identified through traits such as disobedience, irritability, being quick to "fly off the handle," refusal to share materials with others to carry out a task, being inconsiderate and blaming others.

Children with a strong case of opposition have a 1.4 times higher risk of tobacco use, once other factors were taken into account, than in children who showed little oppositional behavior. The risk is 2.9 times higher for cocaine abuse and 2.1 times higher for cannabis abuse. The authors pointed out that the mothers' evaluations gave further important information in relation to the teachers' evaluations. Some kids who were actually described as highly oppositional by their mothers, but not at all by their teachers, also ran a bigger risk of substance abuse and addiction.

Link Between Inattention And Smoking

The link between inattention and smoking was an important correlation also found by the study. There was a 1.7-fold increased risk of developing an addiction to tobacco for children that were very inattentive. The intensity of nicotine addiction in the future is also revealed from the degree of inattention. The researchers' hypothesis that inattentive people would use tobacco as a "treatment" to help them concentrate was supported by the link between inattention and smoking.

Dr. Pingault concluded:

"If other studies can establish a chemical relation of cause and effect between ADHD symptoms and smoking, we could suppose that treating inattention symptoms would make it easier to quit smoking. Until this is demonstrated, our study's findings nonetheless suggest that the prevention or treatment of inattention and opposition symptoms in children could reduce the risk of smoking and drug abuse in adulthood."

Written by Sarah Glynn