Trajectories of criteria of nicotine dependence from adolescence to early adulthood.

BACKGROUND: To identify patterns and correlates of developmental trajectories of DSM-IV nicotine dependence criteria from adolescence to early adulthood.
METHODS: The analytical sample of lifetime smokers (N=877) is from a longitudinal cohort of 6th-10th graders drawn from an urban school system. Subjects were interviewed 5 times at 6-month intervals and once 4.5 years later. Growth mixture models were estimated to identify trajectories of DSM-IV nicotine dependence criteria over ages 12-23.
RESULTS: A four-class solution fitted the data best: No dependence criteria (class 1, 32.0%); early onset/chronic course (class 2, 26.1%); early onset/remission (class 3, 15.4%); late onset (class 4, 26.5%). There appeared to be three critical periods. At ages 12-15, symptoms increased rapidly. As of age 16, the early onset/chronic class stabilized at high levels of symptoms, the early onset/remission class started its symptomatic decline, and the late onset class experienced a sharp increase in symptoms. At age 20, there was a convergence in the prevalence of symptoms experienced at high (classes 2 and 4) and low levels (classes 1 and 3). Extensiveness of smoking and marijuana use were associated with higher baseline levels of nicotine dependence criteria. Anxiety disorders were associated with all three symptomatic trajectories. Parental smoking and nicotine dependence were associated specifically with the early/chronic class, while pleasant initial sensitivity and earlier onset ages of cigarette and marijuana use characterized the two early onset classes (2 and 3).
CONCLUSIONS: Trajectories of dependence criteria constitute an advantageous phenotype for research and intervention over static summaries of smoking behaviors.