Published Source

"People who begin drinking and using marijuana regularly prior to their 15th birthday face a higher risk of early pregnancy, school failure, substance dependence, sexually-transmitted disease and criminal convictions that lasts into their 30s, according to a study co-authored by Carnegie Mellon University Professor Dan Nagin." Source: "Early Exposure to Drugs, Alcohol Creates Lifetime of Health Risk; Carnegie Mellon Professor Co-Authors New Study on Teen Drinking, Drug Abuse. "Ascribe Newswire: Health 16 Oct. 2008: 4. Health Source - Consumer Edition. EBSCO. Web. 23 Mar. 2010.

The study consisted of observing nearly 1,000 New Zealand teenagers from their birth until age 32. Nearly half of said teenagers were troubled, but the other half were average, everyday, normal teens. Yet, they both ended up with similar life and health issues by the time they were age 30. From Nagin's point of view, this meant that early "teenage experimenting"could quickly turn into something much more serious. His data found that "good" kids who didn't have behavioral issues or a bad home life but who began using drugs and alcohol before age 15 wound up being 3.6 more likely to be dependent on said substances, as well as be more likely to end up in trouble with the law as well as contract a sexually transmitted disease. This meant, however, that Nagin was not concerned about teenagers who casually tried drugs and alcohol at parties or only a few times rather than regularly before age 15.