The influence of cigarette smoking in mental health has not been entirely studied yet. However, sleep disturbance is an established cause of mental illness. This review aims to provide an overview of previous investigations on cigarette smoking and its effect on sleep, and use it as an evidence of its influence on central nervous system.
Using Pubmed as database we selected articles written (1) in English, (2) published after 1997, and (3) stating the relationship between “sleep” and “cigarette smoking” or “sleep” and “nicotine” as main subject.
Outcomes from 33 selected articles were organized according to the different ways in which cigarette smoking can affect sleep and allowed us to establish a correlation between subjective sleep complaints and objective sleep disturbance. Smokers not only seem to have daytime sleepiness more frequently but also less total sleep time, longer latency to sleep onset, and an altered polysomnography pattern (decrease of slow wave sleep, a extension of REM sleep latency, an increase of α-frequencies and reduction of δ-frequencies), comparing to nonsmokers. Most of these alterations can also be founded in nonsmokers after administration of 24-hour nicotine patches (absence of acute withdrawal) and after exclusion of any kind of breathing disorder.
Sleep disturbance in smokers is manly caused by direct influence of nicotine in sleep-wake cycle neurons. Further investigations targeting a better understanding of how nicotine could affect neural basis of behavior and biological rhythms are needed.
*Faculty of Medicine, University of Porto, Hospital S. João
†Department of Psychiatry, Hospital S. João, Porto, Portugal
The authors declare no conflict of interest.
Reprints: Miguel Costa, MD, Faculty of Medicine, University of Porto, Alameda Professor Hernâni Monteiro, Hospital S. João, 4200-319 Porto, Portugal (e-mail: firstname.lastname@example.org).