Effects of smoking cessation on reward processing

Research on nicotine addiction indicates greater ventral striatal activity in smokers compared to non-smokers in response to smoking-associated cues but blunted reactivity to non-drug rewards (David SP et al., Biol Psychiatry 2005; 58: 488–49; Martin-Soelch C et al., Eur J Neurosci 2003; 18: 680–688). However, it is still unclear how reward processing changes after smoking cessation. The aim of the present study was to examine neural correlates of reward anticipation and cue reactivity in non-smokers and nicotine-dependent smokers before and three months after smoking cessation. Nineteen smokers and 20 non-smokers performed two paradigms on a 1.5 T scanner: Monetary and social reward anticipation were investigated using the Monetary and Social Incentive Delay task(Knutson B et al., Neuroimage 2000; 12: 20–27; Spreckelmeyer K et al., SCAN 2009; 4: 158–165). The second paradigm examined cue reactivity by presenting blocks of smoking-related, neutral or sexually arousing pictures. All smokers took part in a smoking cessation course. Nine smokers who succeeded in staying abstinent for three months underwent a second fMRI scan with the same paradigms. During both monetary and social reward anticipation smokers showed weaker activity of the NAcc compared to non-smokers. However, in response to smoking-associated pictures stronger neural responses were found in the caudate nucleus. For both paradigms no effect of smoking cessation could be detected.