A new study has said that children who try drugs or alcohol before age 15 run a greater risk of being substance-dependent as adults, contracting sexually transmitted diseases, dropping out of school or being convicted of a crime.
And girls who dabble in drugs and alcohol early on are more likely to become pregnant before they are 21, added the study, published in the October issue of Psychological Science, which followed 1,037 children from the age of three until 32.
At ages 13 and 15, the youngsters were asked if they had sniffed glue, gasoline or other inhalants, of if they had used illegal drugs or drunk alcoholic beverages in the past year.
The children were also assessed for conduct disorders - fighting, bullying, destroying property, telling lies, truancy and stealing - before their teen years, and their family history, including whether either parent had a criminal record and whether the child was mistreated.
Children who tried alcohol or drugs early on "were two to three times more likely than non-early-exposed adolescents to be substance dependent, to have herpes infection, to have had an early pregnancy, and to have failed to obtain educational qualifications," the study showed.
Youngsters who were exposed to drugs and alcohol before 15 also had "significantly more criminal convictions" than those who were not.
But although teens with a history of behavior problems were twice as likely to try drugs or alcohol prior to age 15 as were youngsters with no conduct-problem history, half the children who dabbled with drink and drugs early on had no prior history of behavior issues, the study found.
"Findings from this study are consistent with the message that early substance use leads to significant problems in adolescents' future lives, or the message that drugs are bad for kids, versus the message that young adolescents with a history of problems are just more likely to use drugs early and experience poor outcomes," said the study's lead author, Candice Odgers of the University of California, Irvine.
"Even adolescents with no prior history of behavioral problems or family history of substance abuse problems were at risk for poor health outcomes if they used substances prior to age 15," she said.
Alcohol was the substance most commonly abused by the young teens.