Poor impulse control may be pre-wired in some teenagers, according to a new study by Dr Robert Whelan and colleagues from The University of Vermont. They researchers have identified brain networks that are linked to impulse control and drug addiction, which may exist even before someone is exposed to alcohol or drugs.
As part of this study, the researchers performed brain imaging on almost 1,900 14-year-olds. They used a functional MRI, which permitted them to see how different parts of the brain work together. The teens were asked to perform repetitive tasks, and then were asked to stop mid-task, while the researchers measured their ability to do so. People who abuse drugs or alcohol tend to perform poorly on this test.
The study identified teens who had previously been exposed to alcohol, illicit drugs or nicotine, and who could recognise specific brain patterns linked with early experimentation with these substances. Teens who had poor impulse control, but did not have a history of substance abuse, had similar brain images to those teens who already had used these substances.
Dr Robert Whelan said the findings suggest it may be possible to identify teens at risk of substance abuse, before they start. The study also included teens with attention deficit hyperactivity disorder (ADHD). The researchers found the brain networks of teens with ADHD were different than the ones associated with early substance abuse. Previous research has indicated that people with ADHD are at increased risk of substance abuse and alcoholism.
Source: Adolescent impulsivity phenotypes characterised by distinct brain networks Robert Whelan, et al. Nature Neuroscience Published online 29 April 2012