CHRNA4 and nicotine dependence: A schizophrenia-specific neural foundation for the pathophysiology of tobacco addiction in patients is also endorsed by the findings that patients extract higher levels of nicotine from their cigarettes compared with control smokers,49 and that it may not be effective to use the same brain stimulation target (ie, the DLPFC) in patients as in controls to successfully treat nicotine dependence.50 The nicotinic acetylcholine receptor (nAChR) may play a key role in explaining functional differences observed between smoking patients and controls.