Tobacco is a highly addictive substance. Clinical features of dependence can emerge even during the earliest phases of smoking initiation [1
]. The occurrence of nicotine dependence symptoms among adolescent smokers forms an important barrier for smoking cessation [3
]. Therefore, greater insights into the epidemiology and aetiology of nicotine dependence among adolescent smokers may have important implications for smoking prevention and cessation interventions among adolescents.
The most commonly used self-report measures of nicotine dependence, including the assessment proposed by the Diagnostic and Statistical Manual of Mental Disorders [6
] and the Fagerström Tolerance Questionnaire (FTQ) [8
], are not designed to measure the earlier stages of nicotine dependence; instead, they assume that a more established smoking pattern is required to yield the key features of nicotine dependence. Such characteristics make the measures less appropriate to assess dependence symptoms among adolescents as nicotine dependence symptoms may already be present among early smokers, but may not have reached a diagnosable level. Moreover, these measures generate a classification of low to high levels of dependence, implying that nicotine dependence varies only in severity and not necessarily in nature.
However, a recent study involving an adolescent smoking sample found that, when using a measure specifically developed to assess multiple features of nicotine dependence among adolescent smokers, distinct nicotine dependence symptom profiles could be distinguished [9
]. By measuring symptoms indicative of behavioural dependence (when, where, and how much one smokes), craving, and withdrawal, it was shown that different patterns of symptoms were associated with increasing differences in severity of dependence. Results of this study defined four distinct, yet stable, nicotine dependence subtypes that could be characterized by quantitative as well as qualitative differences. For example, the presence of behavioural dependence appears to indicate more severe dependency than the presence of withdrawal symptoms alone [9
]. In addition, a regular and more established smoking pattern did not seem to be a prerequisite for the occurrence of withdrawal symptoms; a substantial group of adolescents, despite displaying a considerable behavioural dependence and a high level of craving, did not seem to experience withdrawal symptoms. The symptom profiles were similar for both males and females, but differentially associated with previously identified correlates of nicotine dependence. Differential links of the four subtypes were found with regard to smoking uptake and cessation.
The identification of profiles in reference to nicotine dependence symptoms among adolescent smokers may provide some advantages over the use of counting symptoms to measure severity without taking the type of symptoms into account. First, the identification of different symptom profiles may enable a better understanding of the possible underlying genetic and psychosocial factors of nicotine dependence [10
]. Twin studies suggest that genetically based differences in reaction to nicotine moderates the likelihood of taking up smoking [11
]. Not everybody exposed to nicotine becomes dependent. Similarly, some are stimulated by nicotine, whereas others are calmed or even depressed by it [13
]. Such differences in nicotine effects may be reflected in distinct symptom profiles. Second, classification of symptom profiles may enable the tailoring of intervention efforts to specifically target those symptoms most common among the different subtypes of adolescent smokers [14
]. To increase insights into the aetiology of nicotine dependence, as well as design optimal ways of targeting nicotine dependence among adolescent smokers, it is essential to determine early predictors of nicotine dependence symptom profiles [9
According to the Diathesis Stress model [15
], the occurrence of problem behaviours or disorders is the result of the interaction between a vulnerable hereditary predisposition and precipitating events in the environment. Assuming that differences exist in the genetic basis of symptom profiles, different personality dimensions may predict nicotine dependence profiles. Personality has a strong genetic basis [16
], and personality traits are reported to be associated with the initiation and maintenance of smoking in both adolescents and adults [19
]. More specifically, several studies have found that smokers tend to be more neurotic and more extraverted than non-smokers. One possible explanation for this is that individuals scoring high on extraversion may smoke because they seek stimulation while those scoring high on neuroticism may smoke to reduce tension and anxiety [22
]. With respect to adult smokers, researchers have suggested that, apart from smoking initiation and maintenance, personality traits such as neuroticism and extraversion may also be important in the development of dependence [25
]. Thus, the first goal of the current study is to examine the effect of extraversion and neuroticism on the development of nicotine dependence symptom profiles in adolescent smokers.
As posited by Social Cognitive Theory [27
], social environmental factors may also be important. With regard to smoking behaviour in adolescents, exposure to smoking by significant others is related to the development of nicotine dependence symptoms. Children had a higher risk of becoming nicotine dependent from adolescence to early adulthood when their mother had ever smoked, been a daily smoker, or was dependent on nicotine [28
]. Having smoking peers was also associated with higher levels of nicotine dependence in adolescents [28
]. Meanwhile, the Diathesis Stress Model indicates that the smoking of parents and peers may also exacerbate or precipitate the links between personal dispositions and nicotine dependence according to a person-environment interactional perspective. Hence, the second goal of the proposed study is to examine the additive and interactive effect of having a smoking mother or having smoking friends in addition to the personality traits of extraversion and neuroticism.
To pursue these study goals, the current study examines individual and environmental factors as possible predictors of nicotine dependence symptom profiles among adolescent smokers. A clearer understanding of these factors can provide an important foundation for and contribution to developing effective tailored intervention methods for targeting smoking among adolescents.