Event time-series relationship between cigarette smoking and coffee drinking.

Eight subjects resided in a programmed laboratory environment for seven to twelve successive days during which time cigarettes and coffee were freely available. An event time-series analysis based upon instances in time of each substance's use revealed a relationship between cigarette smoking and coffee drinking: a coffee-drinking event tended to occur late in the inter-cigarette interval, and a cigarette-smoking event was most probable during the twenty minutes immediately following a coffee-drinking event.