Short term patterns of early smoking acquisition.

Objective: To describe short term patterns of smoking acquisition exhibited by adolescent smokers.
Design: Interview records from the prospective development and assessment of nicotine dependence in youth study were examined retrospectively. Interviews were conducted three times per year over 30 months.
Subjects: 164 students in grades 7-9 (ages 12-15 years, 86 girls, 78 boys) who had used cigarettes at least twice.
Main Outcome Measures: A continuous timeline of smoking activity, beginning with the subject's first use of tobacco and continuing through follow up, was translated into six patterns--abstinent, sporadic, occasional, daily, escalating, and intermittent. Outcome measures were the proportion of subjects starting/ending in each pattern, and the number of transitions per subject between patterns.
Results: There was a general but discontinuous progression from infrequent to more frequent use, with many interspersed periods of not smoking. Escalation to daily smoking was common after the development of dependence symptoms, but was rare among those who did not have symptoms. After the appearance of symptoms, both transitions to heavier daily smoking and attempts at cessation increased.
Conclusions: Movement to heavier, more frequent smoking is generally unidirectional, although many youths attempt to quit one or more times. The appearance of any symptom of dependence altered the subsequent pattern of smoking behaviour. Future investigators might consider using more frequent data points and a continuous timeline to track smoking behaviour.