Health-related behavior of adolescents: change over time.

A longitudinal study of the changes in health-related behavior in Israeli adolescents was undertaken in a large, comprehensive secondary school. The incidence of starting to smoke and its relationship to the development of sexual behavior was assessed. Smoking, use of drugs, sexual behavior, and drinking of alcoholic beverages at the age of 16 years was related to dropout from secondary school during the 2-year study period. The possibility of developing a model of adolescent risk behavior and its relevance to planning of health and educational services is discussed.