In many cases, teenagers’ drug use and sex behaviors may precede the development of Depression, new research suggests. The findings challenge the belief that depressed teenagers engage in sex and drugs as a means of “self-medicating” their mental health condition.

“Sex and drug use are more dangerous in some ways, I think, than we thought,” said study author Dr. Denise D. Hallfors, of the University of North Carolina at Chapel Hill.

“This is a wake-up call for parents and others to say experimenting with these behaviors is not a good idea,” she added.

According to the 2003 Youth Risk Behavior Surveillance survey, almost half of high school students throughout the nation have had intercourse, 45 percent have consumed alcoholic beverages and 22 percent have used marijuana at some point during the previous month. Further, 29 percent have experienced depressive symptoms, including feelings of sadness and hopelessness that lasted for two weeks or more and led them to stop participating in normal activities.

To investigate whether such feelings of Depression preceded or followed teens’ participation in drug use, sex and other risky behaviors, Hallfors and her colleagues analyzed data from the National Longitudinal Study of Adolescent Health, which included nearly 13,500 youth in grades 7 to 11. The students were first interviewed in 1995 and re-interviewed the following year.

The investigators found that the teens’ use of sex and drugs “predicted an increased likelihood of Depression,” they report in the American Journal of Preventive Medicine. Depression, on the other hand, did not appear to predict sex and drug use behaviors among the teens.

Overall, about 10 percent of students reported experiencing depressive symptoms at first interview and a similar proportion reported the same the following year. Teenagers who reported experimenting with substances or sex in 1995 were more likely to report depressive symptoms in 1996 than were abstainers, those who reported never having used alcohol, tobacco or drugs or never engaging in sexual intercourse.

The association between such risk behaviors and Depression was also gender-specific, study findings indicate.

Girls who initially reported experimenting with substances or sex, and those who initially reported using alcohol were up to three times more likely to be depressed the following year than were their abstainer peers. What’s more, girls who reported having had multiple sex partners and engaging in intravenous drug use were up to 11 times more likely to be depressed during the follow-up interview.

The same was not true among their male counterparts, however.

In contrast, boys who reported frequent marijuana use and those who reported both frequent marijuana use and multiple sex partners, were up to four times as likely to be depressed at second interview than were their peers who abstained from such behaviors, the report indicates.

“The present analyses provide strong evidence to support the hypothesis that adolescent sex and drug behaviors may play a causal or mediating role in the development of adolescent depressive disorders,” Hallfors and her co-authors write.

Contrary to previous reports, the current findings suggest that “sex and drugs come first,” she said.

Further, experimenting with substances and/or with sex is “very risky” for girls in particular, Hallfors added.

For parents, she offered this advice: “Monitor your children’s behavior.”

“They are at an age where they want to experiment and if there’s lots of opportunities for them to experiment they probably will,” Hallfors said.

SOURCE: American Journal of Preventive Medicine, October 2005.