Tobacco smoking in non-psychotic patients with suicidal ideation

Recent studies have found a higher incidence of suicidal ideation/plan/attempt and non-suicidal self-injurious behavior among smokers (Poorolajal et al., 2016; Marin et al., 2020). People with mental health problems have been shown to be one of the most smoking populations (Szatkowski et al, 2015). At the same time, the presence of a mental disorder is an independent predictor of the occurrence of suicidal ideation (Klonsky et al, 2017). An important question about the impact of nicotine consumption on the course of self-Injurious thoughts and behaviors in persons with non-psychotic mental disorders remains unclear. The aim of the study is to evaluate the influence of tobacco smoking (TS) on the risk of lifetime suicidal plan (SP), attempt (SA) and nonsuicidal self-injury (NSSI) in patients with nonpsychotic mental disorders (NPMD) and suicidal ideation (SI). Four hundred and 78 consecutive patients with NPMD and SI were included. All patients were evaluated by a psychiatrist, underwent Self-Injurious Thoughts and Behaviors Interview (SITBI) as well as semi-structured interview designed to gather information on demographic and biographical features. Mann-Whitney, chi-square test and stepwise logistic regression were used as statistical methods. The mean age of the sample was 28 (11.46) and most of the patients were female 417 (97.2%). Lifetime TS was reported by 324 (67.8%) patients. We found no differences between smokers and non-smokers in age, gender, educational and occupational statuses, as well as the diagnoses of mental disorders and their number (Tab.1). SP, SA and NSSI were significantly more common in patients with lifetime tobacco smoking history. No significant differences were found in age of onset of self-injurious thoughts and behavior, and total number of SP, SA and NSSI between lifetime smokers and non-smokers (Tab. 2) Stepwise logistic regression analysis revealed an association of lifetime TS with lifetime SA and NSSI, but not with SP (Tab: 3). In consistence with previous studies (Sankaranarayanan et al., 2015; Marin et al., 2020), our results suggested that lifetime tobacco smoking is strongly associated with an increased risk of suicidal and non-suicidal self-injurious behavior. Moreover, we showed suggested that tobacco smoking involved in transition from ideation to action. It is proposed that smoking may increase the risk of suicide through a biological pathway - decreasing the activity of the serotonergic system of hippocampus, reduce brain serotonin function and activate of the hypothalamo-pituitary-adrenal axis (HPA). Thus, nicotine may be able to activate the attenuated responsiveness of the HPA axis to psychological stress (Poorolajal et al, 2016). History of lifetime TS in patients with NPMD and SI is associated with an increased risk of suicidal and nonsuicidal self-injurious behavior.