Smoking May Be an Independent Risk Factor
for Suicidality

Smoking may be an independent risk factor for suicidality, new research suggests.

A longitudinal study presented at the Anxiety Disorders Association of America 30th Annual Conference shows a strong association between smoking and suicidality in a cohort of 3021 adolescents and young adults aged 14 to 24 years at baseline.

The Early Developmental Stages of Psychopathology study, a prospective, longitudinal study, showed that prior occasional, regular smoking and nicotine dependence were associated with an increased risk for the onset of suicidal ideation, with odds ratios (ORs) ranging from 1.5 to 2.7.

Prior regular smoking and nicotine dependence were also associated with the subsequent first onset of suicide attempts (ORs, 3.1-4.5). According to the investigators led by Roselind Lieb, PhD, preexisting suicidality was not associated with subsequent smoking or nicotine dependence.

"Smoking increases the risk for subsequent suicidality. We have found it is a risk factor independent of other psychopathologies or other drug use,” Dr. Lieb, professor of epidemiology and health psychology, University of Basel, Switzerland, told Medscape Psychiatry.

The study appears to confirm results from a previous 10-year, longitudinal study published in 2005 that showed that current daily smoking, but not past smoking, predicted the subsequent occurrence of suicidal thoughts or attempts independent of major depression, prior substance use, and suicidal predisposition (Arch Gen Psychiatry. 2005;62:328-334).

Dose-Response Relationship

To further investigate the potential link between smoking and suicidality, Dr. Lieb and colleagues used baseline (T0), 1-year (T1), 4-year (T2), and 10-year (T3) follow-up data. Regular smoking, nicotine dependence, suicidal ideation, and suicide attempts were assessed using the standardized Munich-Composite International Diagnostic Interview.

Analyses were based on logistic regression controlling for age and sex and additionally for alcohol and illicit substance use disorders, as well as major depression.

Longitudinal data from 2210 subjects were available for this study. Of these subjects, 33% (at T0), 44.7% (at T2), and 50.5% (at T3) were regular smokers. The trend was similar for nicotine-dependent subjects: 16.9% (at T0), 23.5% (at T2), and 28.3% (at T3).

In terms of suicidality, 10.1% (at T0), 13.8% (at T2), and 17.4% (at T3) reported cumulative suicidal ideations, and 1.8% (at T0), 4.8% (at T2), and 5.5% (at T3) reported suicide attempts.

The analyses of the 10-year follow-up data indicate that there is a dose-response relationship between the duration of smoking and suicidality.

For example, 7% of respondents with a former nicotine dependence (before T2 and during follow-up) attempted suicide, compared with 3.4% of respondents who were never dependent (OR, 2.12; P < .05). This rate increased from 10.1% for respondents who developed a new dependence during follow-up (between T2 and T3) to 16.8% for those who were former dependent smokers and remained so during follow-up.

Further studies are needed to determine the underlying mechanisms, but Dr. Lieb and colleagues speculate that the link may be due to "a common genetic vulnerability within the 5HT [serotonin] system, predisposing smokers to suicidality, or by reduced MAO-A and -B [monoamine oxidase inhibitors A and B] levels, predisposing smokers to 5HT dysfunction."

This study has the best available data to show that smoking precedes an increase in suicidality,” acknowledged Jurgen Hoyer, PhD, professor at the Clinical Psychology and Psychotherapy Institute, University of Technology, Dresden, Germany, who was not associated with the study.

However, he added, “it’s not clear whether smoking may be some attempt to cope with the conditions which later on lead to suicidality,” he told Medscape Psychiatry.

The study was supported by the German Ministry of Education and Research. Dr. Lieb and Dr. Hoyer have disclosed no relevant financial relationships.

Anxiety Disorders Association of America (ADAA) 30th Annual Conference: Abstract 183. Presented March 5, 2010.

Authors and Disclosures- Journalist

Crina Frincu-Mallos, PhD, is a freelance writer for Medscape Medical News.

-From: “ Smoking May Be an Independent Risk Factor for Suicidality”,Crina Frincu-Mallos, PhD, Medscape Psychiatry, March 12, 2010, http://www.medscape.com/viewarticle/718340 retrieved 3/15/10.

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