Comparing the reinforcing efficacy of nicotine containing and de-nicotinized cigarettes: a behavioral economic analysis.

RATIONALE: Smoking-related respiratory stimuli produced by de-nicotinized cigarettes may function as conditioned reinforcers, but behavioral data on such reinforcing effects are limited.
OBJECTIVES: The present experiment compared the reinforcing efficacy of cigarettes that provided only smoking-related stimuli (de-nicotinized cigarettes) and cigarettes that provided both smoking-related stimuli and nicotine.
METHODS: Eight human subjects responded on a progressive-ratio schedule in which the number of plunger pulls required for standardized cigarette puffs increased across sessions. In one phase, the breakpoints, number of puffs earned per session, peak response rates, ratio producing peak response rates, and the elasticity of demand for cigarette puffs were compared for nicotine-containing and de-nicotinized cigarettes when each cigarette type was the only one available. In another phase, subjects chose between the two cigarette types at some of the prices examined in the previous phase.
RESULTS: Nicotine-containing and de-nicotinized cigarettes produced similar measures of reinforcing efficacy when each was presented alone, but there was a strong preference for nicotine-containing cigarettes when subjects were given a choice.
CONCLUSIONS: These data support suggestions that smoking-produced sensory stimuli may function as conditioned reinforcers and that the relative reinforcing efficacy of cigarettes is determined by the combined effects of the nicotine/conditioned reinforcing complex provided by smoking.