The data and analyses presented rely heavily on the National Youth Survey, a 10-year longitudinal study involving a national sample of adolescents. The study examines what patterns of joint delinquent-ADM (alcohol, drug, and mental health) problems are found within the adolescent population, as well as what proportion of youth exhibit each multiple-problem pattern and how youth are exhibiting these patterns distributed in the general population by age, sex, race, class, and place of residence. Also addressed are how these patterns differ regarding the frequency of each type of behavior. The study considers whether there is a particular temporal order or developmental sequence in the onset of these behavior that is more likely than others and whether a common set of causes for these problems can be identified. Finally, the study examines the predictive effect of joint involvement in these behaviors on subsequent long-range "career" or chronic involvement in crime or ADM disorders. Methodological, theoretical, policy, and future research implications are drawn from the findings. Chapter tables, 220 references, appended supplementary information, subject index, author index.