Casual teen sex linked to suicidal thoughts.

• Position: Mental Health

Poor mental health and casual sex feed off of each other in teenagers and young adults, with each one contributing to the other over time, maintains a study in the Journal of Sex Research. Teens who show depressive symptoms are more likely than others to engage in casual sex as young adults--and those who engage in casual sex are more likely to consider suicide seriously later on.

"Several studies have found a link between poor mental health and casual sex, but the nature of that association has been unclear," says Sara Thoma, lead author of the study. "There's always been a question about which one is the cause and which is the effect. This study provides evidence that poor mental health can lead to casual sex, but also that casual sex leads to additional declines in mental health."

One surprising finding is that the link between casual sex and mental health is the same for men and women. "That was unexpected...