Psychotic symptoms are linked with daily use of tobacco, according to a study recently published in the Journal of Clinical Psychiatry. This correlation could not be explained through either schizophrenia or prior psychosis-like experiences.
This population-based study included 34,653 individuals from Wave 2 of the National Epidemiologic Survey of Alcohol and Related Conditions. Smoking was significantly associated with 14 out of 22 selected psychosis-like experiences, a relationship that persisted even after sociodemographic, drug use disorder, and past-year cannabis use adjustments.
Over a quarter of nonsmokers reported ≥1 psychosis-like experience (26.33%), while this figure was higher in former smokers (27.48%) and even higher among current smokers (39.09%), yielding an odds ratio of 1.33 (95% CI, 1.23-1.45) for current smokers vs never-smokers.
The differences in symptoms did not present a clear answer. For example, current smokers were 1.95 times more likely to experience hallucinations than former smokers (95% CI, 1.01-3.76), while the difference was much lower between current and never-smokers (odds ratio 1.21; 95% CI, 0.64-2.26). Overall, current smokers did show higher rates of all 22 psychosis-like experiences than did former smokers or never-smokers. Only 3.42% of never-smokers reported ≥5 psychosis-like experiences, compared with 8.56% of smokers (adjusted odds ratio 1.56; 95% CI, 1.32-1.84).
Researchers performed the original study between 2004 and 2005, and they used the Alcohol Use Disorder and Associated Disabilities Interview Schedule-IV to assess participants. Among the 22 psychosis-like experiences were delusions, grandiosity, hallucinations, and suspiciousness. Smoking status was classified as never, former, and current, while tobacco was divided into cigars, cigarettes, pipe, snuff, and chewing tobacco. In analysis, sociodemographic information and medical covariates were simultaneously entered for multivariate logistic regressions.
The study researchers conclude that “daily nicotine consumption was associated with various psychotic symptoms. Further longitudinal study is required to confirm our findings. Tobacco smoking is a potent and modifiable cause of morbidity, but its prevalence is still elevated in people with mental health problems compared with those without them. There is a need to identify the potential neurobiological mechanisms by which smoking and [psychosis-like experiences] are associated, for patients and from a public health perspective.”
Mallet J, Mazer N, Dubertret C, Le Strat Y. Tobacco smoking and psychotic-like experiences in a general population sample. J Clin Psychiatry. 2018;79(6).