Study delves into the link between smoking and suicidal behaviors

Reviewed by Emily Henderson, B.Sc.Jun 25 2021

Psychiatry and Clinical Psychology residents Iván Echeverria, Miriam Cotaina and Antonio Jovani, from the Hospital Provincial of Castellón, doctor Ana Benito and doctor Gonzalo Haro from the TXP research group of the CEU UCH, and doctor Rafael Mora, have published the results of their latest research: a meta-analysis on suicide, the first cause of external death in Spain.

This time, the study delved into the possible connection between smoking, a toxic habit that is prevalent in our country, and different suicidal behaviors: ideation, planning, suicide attempts and suicides committed.

As much as 19.8% of the Spanish population smokes every day. Considering that numerous studies suggest that smoking increases suicide risk, we believe it is essential to delve into this connection."

Miriam Cotaina,  Asociacion RUVID

After analyzing a total 2,436 scientific articles on this topic, the meta-analysis ultimately includes data from 20 articles with a higher level of evidence as they are prospective studies, involving a total 2,457,864 participants.

Tobacco use, suicide risk factor

Doctor Echeverría explains that "the results show that smoking multiplies the risk of suicide by 2.5. However, this figure seems to decrease in former smokers. This pattern seems to take place across the suicidal spectrum, as the risk of developing suicidal ideation is 1.84 times higher among smokers and just 1.35 times greater among people who have stopped consuming tobacco.

"Meanwhile, doctor Jovani highlights the importance of including this information in suicide prevention plans: "Tobacco is not considered an independent predisposing factor in suicidal risk assessment scales. One of the most used scales in psychiatric emergency services is SAD PERSONS, which includes toxic habits such as alcoholism, but not smoking," he says. "Science must be the light that guides our daily clinical practice, which is why considering the high prevalence of smoking and its effect on suicidal behaviors, the addition of the "T" (tobacco) could be added, turning it into "T-SAD PERSONS".

Smoking women and pandemic: higher risk

Ana Benito adds that "in our clinical practice during the COVID-19 pandemic, we observed a significant increase in suicide attempts, especially among the young female population." The figures of this study show that women who smoke have a higher risk of suicide than males, which makes us consider the extent to which gender differences socially affect suicidal behaviors."

One of the possible biological explanations of the tobacco-suicide connection is the role of nicotine in the central nervous system, which could decrease the levels of serotonin in the hippocampus and modify the enzymatic activity of the neurotransmitters involved in affective processes.

Doctor Gonzalo Haro, head researcher at the TXP group of the CEU UCH, clarifies this: "One of the most backed hypotheses to date in depression and suicide is the decrease in neurotransmitters such as serotonin, noradrenalin and dopamine. Smoking would make these alterations even more prominent, thus having the contrary effect to that sought with antidepressants, causing anxious-depressive symptoms that could be the breeding ground leading to suicide."

Research team

The study has been directed by professor Gonzalo Haro and doctor Ana Benito, from the TXP research group of the CEU Cardenal Herrera university and conducted by Iván Echeverria and Antonio Jovani, psychiatry residents, and Miriam Cotaina, clinical psychology resident, all at the Hospital Provincial de Castellón. Doctor Rafael Mora, head of the Mental Health service at the same hospital, and member of the suicide group of the Valencian Community's regional Universal Health Department, also collaborated. The study was funded by the Research Foundation of the Hospital Provincial de Castellón.