It was widely thought that adolescents considered themselves invincible, and that this belief lead them to try risky behaviors like drugs, drinking and unprotected sex, as they thought their actions would be without consequence. 

University of Minnesota researchers flipped this assumption in a study released Monday.

After interviewing over 20,000 students from grades seven through 12 in 1995 and following up with them in 2001-2002, researchers found that nearly 15 percent of teenagers thought they had less than a 50-50 chance of living past 35, and it was these people who were more likely to participate in dangerous activities. 

Associate Professor in Pediatrics and Researcher Iris Borowsky said to the Star Tribune that this may be because the teens "feel hopeless and figure that not much is at stake." She called the team’s findings surprising and disturbing.