Friday, March 26, 2010

Smoking Is an Independent Risk Factor for Suicide

The feature common to smoking and to suicide is impulsivity, naturally. If that is not true, and smoking is truly an independent risk factor, one wonders if treatments for smoking, such as varenicline, reduce the suicide rate. This would contradict the extremist scapegoating of this medication.

From Medscape Medical News

Smoking May Be an Independent Risk Factor for Suicidality

Crina Frincu-Mallos, PhD

March 11, 2010 (Baltimore, Maryland) — Smoking may be an independent risk factor for suicidality, new research suggests.

A longitudinal study presented here 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.

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