Patterns of substance use among children and youth: a longitudinal study.

This report presents a set of findings from a three wave 36 month longitudinal study on the use of cigarettes, alcohol, marijuana/hashish and other drugs by a population of children and adolescents ranging in age from 9 to 17 at the time of first interview. Gross differences in percentages of subjects reporting using substances across the three data collection intervals are found to be quite small. However, when these differences are examined in detail, it is found that a good deal of initiation of use by some subjects and curtailing of use by others stands behind the relatively small net changes in use from one interval to another. Escalation in substance use, from less mood altering to more mood altering substances, is found to exist, but to appear far less frequently than "initial" multiple drug use. Finally, "intensity" of use of one substance is found to be somewhat related to age and very strongly related to the use of other substances. Limitations of findings due to episodic rather than continuous monitoring of substance use are noted.