Effects of haloperidol on reactions to smoking cues in humans

Both preclinical and clinical evidence suggest that brain dopamine (DA) systems are involved in conditioned responses to drug cues. In smokers, such responses to smoking cues include the subjective urge to smoke and increases in heart rate and reaction time. This study investigated the role of DA in cues associated with smoking and nicotine in cigarette smokers, by acutely pretreating subjects with a DA receptor antagonist. Twenty temporarily abstinent smokers participated in three sessions in which they received haloperidol (HAL; 2 and 4 mg) or placebo before presentations of visual and tactile stimuli related to smoking. HAL (2 mg) attenuated heart rate increases induced by smoking cues, but did not change subjective ratings of smoking urge. HAL (4 mg) also failed to reduce urge to smoke ratings, and did not significantly reduce other cue reactions. These results provide preliminary evidence that acute administration of a low-dose DA antagonist can attenuate some conditioned responses to smoking cues, but not cue-induced urge to smoke.