Effects of cigarette smoking on reward responsivity and cognitive function in brain injured individuals

Abstinence from smoking has been associated with acute impairments of performance in a number of tasks associated with incentive motivation and executive functioning in non-injured participants. The current study aimed to investigate the effects of smoking on various cognitive and motivational measures in 18 brain injured smokers, thus generalising previous findings from non-injured participants. A within-subjects cross-over design was utilised, to compare performance after an acute period of abstinence from smoking with performance after smoking. The test battery included measures of reward responsivity (a card-sorting task providing a behavioural index of incentive motivation), verbal fluency, and working memory. Reward responsivity was enhanced after a cigarette had been smoked compared to when abstinent. Performance on the card sorting task was particularly enhanced when the task was novel. There was no significant enhancement on any other measure. It was concluded that smoking has a direct effect on responsiveness to incentive, which we have found elsewhere to be closely related to motivation in therapy. Implications for clinical neuropsychological assessment and treatment are discussed.