Parents have always suspected it, and now a scientific study has backed them up by showing that dating, sexual activity and drugs do make teens feel older than they really are. Researchers at the University of Alberta in Edmonton, Canada, along with researchers at the University of Victoria, carried out the study.

As a part of the study they surveyed a random sample of nearly 700 adolescents between 12 to 19 years of age from a medium-sized North American city and asked them questions about dating, sexual experience, smoking, alcohol and drug use.

The participants, males and females, were also asked how old they felt compared to their same-sex peers. Survey results indicated that, as is typical for teens, the sample felt older than their chronological age.

Kelly Arbeau, a doctoral student in psychology at the University of Alberta and co-author of the study, said that the results had shown that specific behaviours do have an effect on adolescents and how they act.

"We found that specific behaviours do have an effect on adolescents' self-perceived age. For example, having an older dating partner seems to give a teen a higher subjective experience of age," she said. Such behaviours include sex at a young age, smoking and indulging in substance abuse, "Sexual experience is unequivocally the realm of adult behaviour. So, when teens are having sex and their peers aren't, it can make them feel more adult, more mature than their non-experienced counterparts," she said.