ADHD: Defiance, Not Hyperactivity Linked with Increased Risk of Adult Substance Abuse

There's been a lot of research linking childhood ADD/ADHD with an increased risk of adult substance abuse disorders.

But is everyone with an attention deficit disorder at equal risk of substance abuse and addiction?

That's what researchers at The University of Montreal wanted to know, and to find out they followed 1803 school kids from the ages of 6 to 12 and had teachers and parents evaluate each annually on measures of inattention, hyperactivity an oppositional/defiant behaviors.

They then followed up with each study subject at age 21, to evaluate for substance use and abuse.

The Results

• By age 21, 13.% were alcohol abusers or alcohol dependent, 9.1% were marijuana abusers or dependent, 2.0% were cocaine abusers or dependent and 30.7% smoked cigrettes.
• Compared to children without ADD/ADHD symptoms, children with oppositional or defiant tendencies (such as being very quick to anger, being inconsiderate of others, being unwilling to share etc.) were 2.9 times more likely to grow into adults with cocaine problems, 2.1 times more likely to have a marijuana problem and 1.4 times more likely to smoke cigarettes.
• Children described as very inattentive were 1.7 times more likely to smoke cigarettes at age 21.
• There was no significant link found between inattention and an increased risk of other drug use and no link at all between hyperactivity in childhood and substance abuse at adulthood.

Commentary

Commenting on the significance of the findings, lead researcher Jean-Baptiste Pingault, Ph.D., noted that not everyone with ADHD shares a similar risk of adult substance abuse, saying, “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."

Read the full study results in Molecular Biology.