The argument for smoking prevention among adolescents is based on the observation that, if smoking does not start during adolescence, it is unlikely ever to occur and on data indicating that the probability of cessation among adults is inversely related to age at initiation. Even infrequent experimental smoking in adolescence significantly increases the risk of adult smoking. Once smoking has begun, cessation is difficult and smoking is likely to be a long-term addiction. For example, it has been estimated that the median cessation age, for those born from 1975 through 1979 who begin smoking in adolescence, is 33 years for men and 37 years for women. Based on a median initiation age of 16 to 17 years, the predicted duration of smoking is 16 and 20 years for 50% of the males and females respectively. Prevention of the onset of adolescent smoking is thus an essential component of efforts to reduce the overall prevalence of smoking and its attendant morbidity and mortality. Although there are educational programmes available with demonstrated effectiveness in reducing the prevalence of adolescent smoking over the short term, the longer term evaluations are not as encouraging. The differences in smoking levels between treated and control groups appear to dissipate over time, and disappear completely after six years. Further evaluations of these educational efforts are warranted, with consideration given to methodological problems inherent in such studies (such as potential bias resulting from losses to follow up, and possible effects of interventions other than the one being evaluated). There is, however, also a need to continue to examine research on the etiology of smoking in young people. Research and theory must be directed toward understanding why some individuals smoke and others do not.
Some of the research in adolescent smoking is grounded in theory, whereas