The relationship between level of cigarette consumption and latency to the onset of retrospectively reported withdrawal symptoms

Rationale Subthreshold smokers (who smoke <= 5 cigarettes/day) experience withdrawal symptoms, yet they smoke less than is required to maintain serum nicotine levels. Objectives For study 1, our aim was to determine (1) if adult subthreshold smokers report withdrawal symptoms; (2) how they rate symptom severity; (3) the length of their latency to withdrawal symptoms; (4) and the relationship between level of cigarette consumption and latency to withdrawal. The aim of study 2 was to attempt to replicate the results of study 1 in a nationally representative sample and to compare subthreshold and threshold (>= 6 cigarettes/day) smokers. Methods Study 1 was conducted through telephone interviews. Study 2 was conducted through secondary analysis of data from the National Youth Tobacco Survey (self-administered in schools). Results In study 1, all subjects experienced withdrawal symptoms. The mean number of symptoms was 4.3; mean intensity of each symptom was > 6 (1-10 scale). A quarter of the subjects could go for >= 2 days before experiencing withdrawal. More frequent smokers had a shorter latency to withdrawal (r=-0.43, p < 0.001, n=36). In study 2, 63% of subthreshold smokers reported feeling at least one withdrawal symptom. Median latency to withdrawal was 168 h for subthreshold and 2 h for threshold smokers. A negative correlation between level of cigarette consumption and latency to withdrawal was observed for both groups. Conclusions Although subthreshold smokers experience significant withdrawal symptoms, they can smoke infrequently because symptoms may not appear for one to several days. Consistent with the sensitization-homeostasis theory, low doses of nicotine can suppress withdrawal symptoms over long periods.