Because ADHD can manifest as impulsivity, recklessness, or distractibility, evidence does suggest that teens with untreated ADHD are more likely than their peers to speed, drive without a seat belt, and be involved in car accidents. One study, for example, found that new drivers with ADHD were 62 percent more likely to be in a car accident in their first month of driving than peers without ADHD. On the other hand, research conducted on adults suggests that adequate treatment greatly reduces the risk of ADHD-related car accidents.