Youths who drink alcohol or use drugs before they are 15 years-old are almost three times more likely to develop substance abuse, contract sexually transmitted infections, drop out of school, have criminal records and become pregnant early, a new study shows.
Otago University's Dunedin Multidisciplinary Health and DevelopmentStudy followed 1000 people born in Dunedin in 1972-73.
At age 32, they were asked about their early alcohol and drug use and adult health.
The results showed low-risk children who used alcohol or drugs prior to age 15 were 2.7 to 3.8 times more likely to have "significantly poorer health" as adults.
Children seen as high-risk, those with a history of behaviour problems, were 2.4 to 5 times more likely to have problems.
Early drug users had the most significant adult health problems but early alcohol use also affected adult health.
Paper co-author Professor Richie Poulton said the research showed prevention was required for all children not only those viewed as high-risk.
Fifty per cent of those who used alcohol or drugs before age 15 had no prior history of negative behavioural problems.
