Adolescent initiation into drug-taking behavior: comparisons over a 5-year interval.

Acquisition curves for six substances were compared for adolescents in two samples separated by a 5-year interval. Individual variations in initiation ages were found for different substances, but the general pattern of exposures to drugs was essentially stable over the time interval. The findings suggest that there appears to be a range of first experience with drugs that extends from 13 to 16 years. Special emphasis was given to the implications which the findings have for education and intervention programs, and for further research.