Aims: To examine associations among depressive symptoms, smoking, smoking trajectories and quitting smoking in Hong Kong.
Design: Prospective longitudinal design, with wave 1 at baseline (T1) and wave 2 (T2) 12 months later.
Setting and participants: Form 1 (equivalent to 7th grade in the United States) students, mean age = 12.7 years, n = 1894.
Measurements: Self-reported smoking status, attempts to quit and depressive symptoms.
Findings: At both waves, current as well as ex-smokers had higher depressive symptoms than never smokers. T1 smoking predicted T2 depressive symptoms among those with low baseline depressive symptoms. Depressive symptoms at T1 predicted smoking at T2 among non-smokers at T1. Trajectories were defined by separating participants who were never smokers at both waves ('non-smokers'), those who smoked at both waves ('persistent smokers'), those who smoked at one time but were not smoking at either wave ('past smokers), and those who had never smoked at T1 but reported smoking a year later ('new smokers'). Persistent, past and new smokers had higher depressive symptoms at both waves than non-smokers. Smokers who reported not wanting or trying to quit and those who had been unsuccessful at quitting had higher depressive symptoms at T2 than those who successfully quit.
Conclusion: Our results suggest that depressive symptoms promote tobacco use in Asian adolescents by making it more likely that an adolescent will begin smoking and less likely that she or he will quit. These findings elucidate risk factors in Hong Kong for two important public health concerns for adolescents: smoking and depression.