Peer pressure may be a good thing.

Teenagers who have close friends are more likely to have better health as young adults, according to research from the University of Virginia in Charlottesville. "These results indicate that remaining close to -- as opposed to separating oneself from -- the peer pack in adolescence has long-term implications for adult physical health," wrote study co-author Joseph Allen in the journal Psychological Science. A study found that those who enjoyed high-quality friendships and had a high desire to fit in with their peers during adolescence had far better health at age 27 than those who separated themselves from their peers during the teenage years. This held even after the researchers accounted for other factors, including income, weight and drug use. Why? Strong friendships and a feeling of being part of a group as a teenager may influence adult health by lowering anxiety and stress levels. The study showed only an association -- and not a cause-and-effect relationship -- between having close friends in adolescence and better health as an adult.