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.

The authors have declared no competing interest.

This work was supported in part by UNIST internal funding (1.210046.01) and the National Research Foundation of Korea (NRF-2018R1D1A1B07043582 to Chung). K.B. was partly supported by the National Research Foundation of Korea (NRF-2021R1F1A1063968), Institute of Information & Communications Technology Planning & Evaluation (grant No. 2020-0-01450, Artificial Intelligence Convergence Research Center [Pusan National University]), and Ministry of Education of South Korea (the BK21 Four program, Korean Southeast Center for the 4th Industrial Revolution Leader Education).

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The current study and all the protocols were approved by the Institutional Review Board (IRB) of Ulsan National Institute of Science and Technology (UNIST) (UNISTIRB-19-45-A), and all participants provided written informed consent following an explanation of study procedures.

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