Neuroimaging of Nicotine Dependence: Key Findings and Application to the Study of Smoking-Mental Illness Co-morbidity

Modern neuroimaging techniques offer the opportunity to noninvasively study neuroanatomical and neurofunctional correlates of nicotine dependence and its treatment. In the present review, the most widely used neuroimaging techniques-magnetic resonance imaging (MRI), positron emission tomography, and functional MRI-are briefly described and their strengths and limitations discussed. The use of these techniques has resulted in new insights into the neuropharmacology of tobacco addiction. Studies comparing smokers and nonsmokers have shown that smokers have less grey matter density in frontal brain regions and greater concentrations of nicotinic receptors. Research on the effects of smoking a cigarette confirms that smoking leads to the release of dopamine in brain reward areas and to nicotinic receptor binding. Studies of smoking abstinence have identified functional brain correlates of increased reactivity to smoking-related cues, and worsening of concentration. To date, neuroimaging studies of nicotine dependence among individuals with mental illness have focused almost exclusively on schizophrenia. A conceptual/methodological framework for studying dual diagnosis using neuroimaging measures is provided, with the aim of spurring additional research in this area.