Objective: This study was undertaken to evaluate the association between patterns of day-to-day smoking and drinking among first year college students.
Method: Using 210 days of weekly time-line follow-back diary data, the authors examined the within-person relationships between smoking and drinking. Bivariate time series procedures were utilized.
Results: Findings revealed a high degree of significant cross-correlations between smoking and drinking in which the amount of use of one substance could be predicted by current, as well as past and future use of the other. For the majority of participants, smoking and drinking were positively associated with the alternate behavior. The most common pattern of prediction for individuals was within day (i.e. synchronous correlations). When examining rates of individuals showing significant cross-correlations according to their level of either smoking or drinking, those smoking less than one cigarette on average per day were found to be less likely to demonstrate a synchronous cross-correlation between the two behaviors than those smoking at higher rates. No significant association was found between level of drinking and the rate of significant synchronous cross-correlations between smoking and drinking.
Conclusions: Reports of daily behavior over long periods of time have the potential to provide insight into the more proximal influences of smoking and alcohol use on one another. Future research is needed to establish the specific factors (i.e. third variables) and related mechanisms that may drive both behaviors.