Neural Substrates of Alcohol-Induced Smoking Urge in Heavy Drinking Nondaily Smokers

A strong link exists between cigarette smoking and alcohol use, which may be explained by the experimental observation that alcohol ingestion promotes cigarette craving and precipitates smoking. At the neuroanatomic level, it is unclear where and how alcohol exerts these effects, although the process likely involves the ventral striatum given its function in motivational salience and appetitive reinforcement. In a double-blinded, placebo-controlled, crossover study, heavy drinking nondaily social smokers (ie, light smokers or 'chippers') were examined using functional magnetic resonance imaging after they ingested an acute dose of alcohol or placebo. We probed reactivity in the ventral striatum and other brain regions during exposure to visual smoking vs nonsmoking control cues. We found that alcohol enhanced self-reported ratings of desire to smoke, and in this context, significantly increased ventral striatum responses to smoking compared with control cues. In exploratory analyses, we observed that alcohol dampened orbitofrontal activity across both cue types, whereas dorsolateral prefrontal and anterior cingulate cortex activation to smoking cues was not affected by alcohol. This study bridges a pharmacological challenge approach to the study of brain reactivity to smoking cues, extends prior cigarette cue imaging studies to nondependent smokers, and elucidates a potential neurobiological mechanism to explain the co-consumption of alcohol and cigarettes in nondependent users. Neuropsychopharmacology (2010) 35, 692-701; doi:10.1038/npp.2009.177; published online 11 November 2009