Patterns of drug use from adolescence to young adulthood: III. Predictors of progression.

Abstract

Possible linkages of influence among classes of drugs in the observed sequential progression from adolescence to young adulthood are investigated through event history analyses. Three stages are examined: initiation to marihuana, to the use of other illicit drugs, and to prescribed psychoactive drugs. The data are based on a follow-up cohort of former adolescents representative of high school students in grades 10 and 11 in New York State [USA] who were reinterviewed 9 yr later at ages 24-25. The sequential order between alcohol and/or cigarettes and marihuana reflects not only the effect of the use of legal drugs on marihuana initiation, but also age effects on onset of these drugs, controlling for individual characteristics measured in adolescence; marihuana use by one''s friends in adolescence is an additional important predictor of marihuana initiation. Prior use of marihuana is necessary for progression to other illicit drugs. Multiple factors are involved in the progression to prescribed drugs: adolescent depressive symptomatology and use of other illicit drugs important for both sexes; and maternal use of psychoactive drugs, dropping out of school, and prior use of marihuana of additional importance for women. Although licit drugs influence initiation into marihuana independently of age effects, it is especially for the progression from marihuana to other illicit drugs that the earlier drug is associated with the progression to a higher stage drug.