Initial Nicotine Dependence Has Lasting and Time-Varying Effects on Adolescent Smoking Behavior

Introduction: Recent studies have demonstrated that adolescents can experience symptoms of nicotine dependence (ND) soon after initiating smoking and well before establishing daily smoking patterns. This early-emerging ND strongly predicts future smoking, independent of prior smoking behavior. Previous research has shown that the time-varying effects of concurrent ND on smoking behavior increase over time and with more advanced stages of smoking. However, little is known about the time-varying predictive validity of initial ND for future smoking behavior.

Methods: Data were drawn from the Social and Emotional Contexts of Adolescent Smoking Patterns (SECASP) Study, a longitudinal study oversampling light and novice adolescent smokers. Initial ND was time-invariant and drawn from the baseline wave, and the outcome of smoking frequency was time-varying over 6 years. A number of control variables were also included. The predictive validity of baseline ND for smoking frequency, and the potential changes in predictive validity over time, were examined using time-varying effect models.

Results: ND had a time-varying effect on future smoking frequency, such that its predictive validity was highest initially and declined over time. However, baseline ND remained significantly associated with smoking frequency at all timepoints from baseline through 6 years.

Conclusions: These findings support previous literature showing that early-emerging ND is a strong risk factor for future smoking, and add to current knowledge about how the predictive validity of initial ND changes over time. Though baseline ND significantly decreased over time in predictive validity for smoking behavior, it remained a significant predictor 6 years into the future. These findings highlight the need for early interventions targeted at youth who experience ND symptoms at low levels of smoking.