Scientists at Rockefeller University say that adolescents are more likely to become dependent on the opioid painkiller medication oxycodone than adults, Reuters reported Sept. 17.

Researchers observed self-administration of the drug in four-week-old and 10-week-old mice and concluded that adolescent mice self-administer less oxycodone than adult mice, which suggests increased sensitivity to the drug among adolescents.

The findings also show that mice exposed to oxycodone during adolescence were more sensitive to the drug after later re-exposure as adults -- an indication that the drug triggered lasting functional changes in the developing adolescent brain.

"Together, these results suggest that adolescents who abuse prescription pain killers may be tuning their brain to a lifelong battle with opiate addiction if they re-exposed themselves to the drug as adults," said researcher Mary Jeanne Kreek  in a press release on the study. "The neurobiological changes seem to sensitize the brain to the drug's powerfully rewarding properties."

The research was published online on Sept. 10, 2008 in the journal Neuropsychopharmacology.