- © 2007 Canadian Medical Association or its licensors
André Gervais and colleagues have rightly pointed out that smoking prevention programs targeted to youth have little or no long-term impact on cigarette use because of our incomplete understanding of how and why young people start to smoke.1 Recent developments in the field of chronobiology, however, have enhanced our understanding of the initiation of smoking in adolescents.2
The chronotype (the timing of rest and activity) is regulated by a biological clock that varies considerably from person to person. Genetic differences and environmental influences contribute to the distribution of chronotypes in a given population. Work schedules interfere considerably with most people's sleep preferences. Adolescents are late chronotypes;3 this group shows the largest differences in sleep timing between work and free days. This discrepancy between social and biological time has been called social jet lag. Recent research has revealed that a significant and striking direct relation exists between social jet lag and smoking.2 Therefore, adolescents are at a greater risk of initiating cigarette use than are people in other age groups. We believe that simple behavioural means of adapting social and biological time would largely prevent the initiation of smoking in adolescents and could also play an important role as a smoking cessation strategy.