Study Links Smoking During Pregnancy to Psychotic Behavior Source: ScienceDaily Date: 10/6/09
Mothers who smoke during pregnancy put their children at greater risk of developing psychotic symptoms in their teenage years.
New
research published in the October issue of the British Journal of
Psychiatry shows a link between maternal tobacco use and psychotic
symptoms.
Researchers from
Cardiff, Bristol, Nottingham and Warwick Universities studied 6,356
12-year-olds from the Avon Longitudinal Study of Parents and Children.
All the children completed an interview for psychotic-like symptoms,
such as hallucinations or delusions. Just over 11% of the children
(734) had suspected or definite symptoms of psychosis.
Smoking during
pregnancy was found to be associated with an increased risk of
psychotic symptoms in the children. The researchers observed a
'dose-response effect', meaning that the risk of psychotic symptoms was
highest in the children whose mothers smoked the most heavily during
pregnancy.
The study also
examined whether alcohol use and cannabis use during pregnancy was
associated with a higher risk of psychotic symptoms.
Drinking during
pregnancy was associated with increased psychotic symptoms, but only in
the children of mothers who had drunk more than 21 units of alcohol a
week in early pregnancy. Only a few mothers in the study said they had
smoked cannabis during pregnancy, and this was not found to have any
significant association with psychotic symptoms.
The reasons for
the link between maternal tobacco use and psychotic symptoms are
uncertain. But the researchers suggest that exposure to tobacco in the
womb may have an indirect impact by affecting children's impulsivity,
attention or cognition. They have called for further studies to
investigate how exposure to tobacco in utero affects on the development
and function of children's brains.
It is estimated that between 15 and 20 per cent of women in the UK continue to smoke during their pregnancy.
Dr Stanley
Zammit, a psychiatrist at Cardiff University's School of Medicine and
lead author of the study, said "In our cohort, approximately 19 per
cent of adolescents who were interviewed had mothers who smoked during
pregnancy.
"If our results
are non-biased and reflect a causal relationship, we can estimate that
about 20 per cent of adolescents in this cohort would not have
developed psychotic symptoms if their mothers had not smoked.
Therefore, maternal smoking may be an important risk factor in the
development of psychotic experiences in the population."
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