The present study investigated cigarette smoking among a Greek nation-wide school-based sample of adolescents and the relationship between cigarette smoking status and adolescents' emotional/behavioural problems while considering the potential confounding effects of other important factors (i.e. age, gender, socioeconomic status, parental smoking, leisure time) in order to obtain a more accurate account of this widely reported association. The prevalence rates of current smoking for adolescents aged 12-15 years and those aged 16-18 years were found comparable (i.e. approx. 4% and 24% respectively) to those reported in other Greek studies [2, 31]. The frequency of current smokers was significantly higher among adolescents from low family socioeconomic background and with a smoking parent. These findings are consistent with previous data [30–32]. However, the present study could not detect any significant association between smoking status and adolescents' leisure time . The measurement of leisure time applied here may account for this finding, since it did not include data regarding parental control and surveillance over adolescents' activities outside school and family. Cigarette smoking was associated with higher levels of emotional/behavioural problems and the association was not moderated after controlling for the effects of other covariates. Emotional symptoms, conduct problems and hyperactivity/inattention were all significantly associated with adolescents' current smoking, lending further support to existing literature [5–21, 23–25]. This result also suggests that the association between smoking and emotional/behavioural problems is not confounded by significant predictors for both adolescents' smoking and emotional/behavioural problems, such as age, socioeconomic status and parental smoking.
The reported relationships underlie the fact that it is often the same individuals who engage in risk behaviours such as smoking and present emotional/behavioural difficulties, increasing the harmful effect of these behaviours on human health. The present findings highlight the importance of addressing adolescents' mental health problems in any effective effort for preventing or combating adolescents' cigarette smoking. Instead of dealing with smoking as a more or less normative risky behaviour during this critical period or focusing mainly on peer influences, adolescent health professionals should take into account the complex cluster of problems and needs which possibly burden adolescents and eventually remain unmet.
Certain limitations should be considered in understanding the results of the present study. The cross-sectional design of the study could not demonstrate causal directions between smoking and emotional/behavioural problems. Additionally, as is frequently observed in school-based surveys, there was a tendency for a higher response rate from girls compared with boys. It should be stressed, however, that the methodology of the European project, within which the present study was conducted, achieved a sufficient degree of representativeness to provide reference population values, as provided elsewhere . Moreover, it is possible that factors other than the variables included in the statistical analyses are related to the associations between smoking and emotional/behavioural problems. For example, genetic factors, smoking habits during pregnancy, peers' smoking and personality variables (e.g. coping styles, affect regulation, risk-taking) could mediate or moderate the abovementioned relationship. Finally, tobacco use was not assessed through elaborated measures of smoking behaviour (tracking initiation age and frequency with a longitudinal design), which may have misclassified the smoking status with consequences on the observed associations.