Cigarette smoking as a risk factor for schizophrenia or all non-affective psychoses

Abstract

Background Smoking tobacco is regarded as an epiphenomenon in patients with schizophrenia when it may be causal. We aimed to examine whether smoking status is related to the onset of schizophrenia or the broader diagnosis of non-affective psychosis, including schizophrenia. Methods We used data from The Health Improvement Network primary care database to identify people aged 15–24 between 1 January 2004 and 31 December 2009. We followed them until the earliest of: first diagnosis of schizophrenia (or psychosis), patient left the practice, practice left THIN, patient died or 31 December 2014. Results In men, incidence rates for schizophrenia per 100 000 person years at risk were higher in smoking initiators (non-smoker who became a smoker during the study) than in non-smokers (adjusted IRR 1.94; 95% CI 1.29–2.91) and higher still in smokers (adjusted IRR 3.32; 95% CI 2.67–4.14). Among women, the incidence rate of schizophrenia was higher in smokers than in non-smokers (adjusted IRR 1.50; 95% CI 1.06–2.12), but no higher in smoking initiators than non-smokers. For non-affective psychosis, the pattern was similar for men but more evident in women where psychosis incidence rates were higher in smoking initiators (adjusted IRR 1.90; 95% CI 1.40–2.56) and in smokers (adjusted IRR 2.13; 95% CI 1.76–2.57) than in non-smokers. Conclusions We found an important and strong association between smoking and incidence of schizophrenia. Smoking may increase risk through as yet unknown pathways or smoking may share genetic risk with schizophrenia and non-affective psychoses.

Tobacco Use, Nicotine Dependence, and Cessation Methods in US Adults With Psychosis

“…Compared with adults without psychosis, those with psychosis had a 1.5- to 1.6-times higher adjusted prevalence of past-month any tobacco use and past-month cigarette smoking overall; had a 1.2- to 2.0-times higher prevalence within almost every age, sex, and racial and ethnic group; and had a higher adjusted prevalence of e-cigarette use and any other tobacco product use overall and in most subgroups. A recently proposed bidirectional association that suggested smoking may be causally associated with an elevated risk of psychosis through shared genetic liability to smoking and psychosis 33 , 34 may help explain the present study’s findings. Moreover, people with psychosis may seek nicotine to alleviate the symptoms of their illness or the adverse effects of antipsychotic medications.…”

“…Tobacco Use, Nicotine Dependence, and Cessation Methods in Adults With Psychosis most subgroups. A recently proposed bidirectional association that suggested smoking may be causally associated with an elevated risk of psychosis through shared genetic liability to smoking and psychosis 33,34 may help explain the present study's findings. Moreover, people with psychosis may seek nicotine to alleviate the symptoms of their illness or the adverse effects of antipsychotic medications.…”

Primary Psychosis: Risk and Protective Factors and Early Detection of the Onset

“…Tobacco as well could take part in psychosis risk [13,15,24,62] with a 2-fold increase in risk of schizophrenia or other schizophrenia spectrum disorders and a dose-response mechanism [63]. The mechanism underlying this association is not clear, with some hypotheses in favor of an rGE correlation where a genetic arrangement that favors the development of primary psychosis also favors tobacco smoking for attenuating a specific distress that manifests in the prodromal phase of the disorder.…”

Menthol Flavor in E-Cigarette Vapor Modulates Social Behavior Correlated With Central and Peripheral Changes of Immunometabolic Signalings

“…Many previous studies have confirmed the association between cigarette smoking and neurodegeneration ( Deochand et al, 2016 ; Yu et al, 2016 ; Liu et al, 2020 ), cognition and memory ( Ge et al, 2019 ; Wei et al, 2020 ; Martin Rios et al, 2021 ), and mental disorders, such as attentional deficits ( Joo et al, 2017 ; Lawrence et al, 2021 ) and schizophrenia ( Donde et al, 2020 ; King et al, 2020 ), considering the wide distribution of nicotinic acetylcholine receptors (nAChRs) throughout the brain ( Levin et al, 2015 ). Based on the fact that nicotine is one of the main addictive components of an e-cigarette, there is increasing recognition that e-cigarettes impact brain functions, for instance, e-cigarettes impaired the integrity of the blood-brain barrier (BBB) and exacerbated the cognitive dysfunction ( Chen et al, 2021 ), mental disorders ( Pham et al, 2020 ), vascular inflammation ( Kaisar et al, 2017 ), metabolic imbalance ( Debarba et al, 2020 ), and neurotoxicity ( Ruszkiewicz et al, 2020 ) in the brain of human and animal models, while the effects of ENDS with specific flavor on the behaviors need further disclosure.…”