Heavy smokers 'at risk of depression'
Stubbing out could reduce men's risk of depression
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Monday, 21, May 2007 05:51
Men who are persistent smokers may be at greater risk of developing depression in comparison to people who have never smoked, a Finnish study has suggested.
The study from the Department of Public Health at the University of Helsinki also claims that smokers who quit have an elevated risk of depressive symptoms in the short-term but this risk declines to the level of never-smokers in the longer-term.
Researchers analysed data collected from the Finnish Adult Twin Cohort Project on about 4,000 male and 5,000 female twins, whose health and health behaviour were followed-up through 15 years.
As the data consisted of twins it was possible to test the link between smoking and depression by using twin pairs where the twin without depression served as a matched control for his/her co-twin with depression.
Twins also enabled the scientists to study the genetic influences between any depression/smoking link.
They found that the elevated risk of persistent smoking remained significant among men only.
Dr Tellervo Korhonen from the University of Helsinki said that the "surprising" results could derive "from addiction mechanisms and from other substances than nicotine within tobacco smoke".
"The mechanisms underlying the association between smoking and depression are very complicated. Although nicotine as such may have short term positive effects on concentration and possibly on mood, long term exposure to tobacco smoke may be one risk factor in development of depression," he added.
"However, this mechanism is still relatively unknown. Thus, there is need for further research and evidence in order to make an unambiguous statement that 'smoking cigarettes cause depression'. Examination of potential shared genetic vulnerability for both tobacco dependence and depression is among the further challenges."