Women who smoke are at greater risk of developing major depressive
disorder, according to
new
research published in the October issue of the
British
Journal of Psychiatry.
The researchers studied a group of women in
Australia, who had been followed for a decade as part of the
Geelong Osteoporosis Study.
Among 165 women with major depressive disorder
and 806 controls, smoking was clearly associated with increased
odds for major depressive disorder. Indeed, the odds more than
doubled for heavy smokers (those who smoked more than 20 cigarettes
a day) compared with non-smokers.
The researchers also examined longitudinal
data to determine the risk of women developing a new major
depressive disorder over time. A total of 671 women with no history
of major depressive disorders were studied.
Of the 87 women who were smokers, 13 went on
to develop major depressive disorder. However, among 584
non-smokers, just 38 developed major depressive disorder during a
decade of follow-up.
The researchers concluded that smoking
increased the risk of major depressive disorder by 93%.
Previous research has shown that smoking is a
risk factor for depression. There is also increasing evidence that
smoking may aggravate mental illness or contribute to its onset.
However, most previous studies have involved short time frames, and
this study is the first to investigate smoking using longitudinal
data that extends over a ten-year period.
The researchers observed that depression is a
leading cause of global disease burden, and called for greater
efforts to encourage smokers to quit.