Medical Daily How Long a Teen Believes They Will Live Predicts Future Behavior New research shows teens who believe they will not live a long and healthy life, may actually foreshadow the future. Conducted by lead author Quynh Nguyen of Northeastern University in Boston, the study evaluated data from 19,000 adolescents between the years of 1994 and 1995. Nearly 13-14 years later, researcher followed up with participants.