Individual change amid stable smoking patterns in polydrug users over 3 years.

The pattern of stability/change in smoking status was examined annually in 254 community-dwelling polydrug users over 3 years. Respondents' smoking status was classified as nonsmoker, intermittent smoker, or "everyday" smoker. Results showed that the typical probability of retaining the same smoking status across any two consecutive assessments was: 0.77 for nonsmokers (never smokers and former smokers combined), 0.82 for everyday smokers, and 0.16 for intermittent smokers. The transition matrix proved stable across three observations; the predicted equilibrium distribution matched well with observed distributions. Fifty-five percent of intermittent smokers converted to everyday smoking within a year, but 29% converted to former-smoker status in the same period. No other transition exceeded 12%. Considerable flux in individual smoking status, particularly among intermittent smokers, was observed despite stable prevalence of smoking status in this population. Intermittent smoking status appeared to be a temporary "way station" between the two more stable everyday smoker and nonsmoker classifications. Results challenge current assumptions about "occasional" or "chipper" smokers.