Smoking during pregnancy may lead to child psychosis

Smoking has long been implicated as a cause of many diseases, including in the babies of mothers who smoke. A new study has now linked the emergence of psychotic symptoms in teenagers to smoking by their mothers during pregnancy.

Over 6,000 12-year olds were studied as part of the research. They were asked about the occurrence of psychotic symptoms such as hallucinations or delusions. Just over 11% 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.

Curiously, smoking cannabis during pregnancy seemed to have no link to psychosis, although the number of mothers reported this behaviour was small. Drinking alcohol during pregnancy was linked to psychosis in children, but only in mothers who drank more than 21 units a week in early pregnancy.

The nature of the link between smoking in pregnancy and psychosis in children is not clear. It is estimated that between 15% and 20% of women in the UK continue to smoke during their pregnancy.