November 2nd, 2009 
Teenagers whose mothers smoked during pregnancy are more likely to experiment with drugs, according to a new study.
The research, carried out by scientists at the University of Nottingham, found children exposed to cigarette smoke in the womb were more likely to experiment with alcohol, tobacco and cannabis.
This is because prenatal exposure to maternal smoking may affect the development of the orbitofrontal cortex, a part the brain which evaluates rewards and regulates emotion.
Academics analysed MRI scans from almost 400 teenagers and found that those born to mothers who smoked during pregnancy had a thinner orbitofrontal cortex.
Scientists then found those suffering from a thinning of this part of the brain were more likely to experiment with a wider range of drugs.
The most commonly used illegal substances among the participants in the study were alcohol, tobacco, cannabis, stimulants and psychedelic drugs.
Professor Tomas Paus, senior author of the study at the University of Nottingham, said: “These findings demonstrate significant consequences of prenatal exposure to maternal cigarette smoking on a child’s brain.
“But our findings need to be interpreted with caution: we could only show an association, not a causal effect of maternal smoking on brain and behaviour. Such causality can be, and has been, demonstrated only in experimental models.
“It is also important to note that almost half of the children of mothers smoking during pregnancy showed no differences in the brain and behaviour, suggesting that something protected them from the adverse effect of cigarette smoke.”
