Many adolescents with substance use disorders take serious risks, including drunk driving, fighting, heavy drinking, drug injections, and more. To find out why users take such risks, researchers take pictures of the brains of typically developing adolescents and those who have a substance use disorder, while the adolescents are deciding between doing a cautious behavior or a risky one. The first row in the figure above shows brain activity while the kids are making decisions that lead to cautious behaviors. At that time, in many key decision-making areas of the brain – the colored areas – typically-developing adolescents have more brain activation than youths with substance use disorders. Similarly, while making decisions to do risky behaviors, typically developing adolescents again show more brain activation (second row). The brains of adolescents with substance use disorders don't work as hard as the brains of typically developing youths when they're deciding between doing a risky or a cautious action, and that could help explain why substance-using adolescents tend to take more risks. The researchers are now trying to find out whether those differences in activation are due to the drugs that some adolescents use, or whether the differences were there before the drug use began.