Persistent and reversible impacts of smoking on resting-state EEG in chronic smokers and successful long-term abstainers

Smoking is a severe addictive health risk behavior and notorious for the high likelihood of relapse after attempted cessation. Such an addictive pattern in smoking has been associated with neurobiological changes in the brain. However, little is known whether the neural changes associated with chronic smoking persist after a long period of successful abstinence. To address this question, we examined resting state EEG (rsEEG) in heavy smokers who have been smoking for 20 years or more, past-smokers who have been successfully abstaining for 20 years or more, and non-smokers. Compared with chronic current- or past-smokers, non-smokers showed higher relative power in theta frequency band, showcasing long-lasting effects of smoking on the brain. A few rsEEG features in alpha frequency band also revealed reversible impacts of smoking, such that only current-smokers, but not past-smokers, showed distinctively higher patterns than non-smokers in their relative power, EEG reactivity--power changes between eyes-closed and eyes-open conditions--, and coherence between channels. Furthermore, rsEEG feature differences between current- and past-smokers were accounted for by individuals self-reported smoking history and nicotine dependence. These data suggest long-lasting impacts of chronic smoking on the brain that are dissociable from the neural changes reversible with long-term abstinence.