Smoking and Cognition.

Given the large availability of nicotinic acetylcholine receptors (nAChRs) throughout the brain, and the wide range of neurotransmitter systems affected (norepinephrine, serotonin and dopamine), nicotine influences a wide variety of cognitive domains such as sensorial, motor, attention, executive function, learning and memory. This article reviews current state of the art research on the effects of nicotine upon cognition. There are different neurobiological mechanisms involved in acute/chronic smoking and nicotine abstinence. Smoking reinforcement could be due to the initial cognitive improvement, that is, individuals can learn that smoking temporarily increases cognitive functioning (improving some components of attention and memory). These acute nicotine effects improve (i) cognitive performance above smokers' normal levels, and (ii) cognitive disruption resulting from nicotine abstinence. Both neurobiological effects act as reinforcers to nicotine use, greatly contributing to the development of nicotine dependence. However, heavy smoking is associated with cognitive impairment and cognitive decline in middle age. Future clinical research should investigate the role of positive and negative cognitive effects of nicotine in smoking cessation treatment. This is clearly an important scientific issue, with insufficient current data from which to draw definitive conclusions.