Researchers from Columbia University (CU) in the US evaluated nearly 1,000 cases of schizophrenia and matched controls among offspring born in Finland from 1983-1998.
Results showed that a higher maternal nicotine level in the mother's blood was associated with an increased risk of schizophrenia among their offsprings, researchers said.
The study provides the most definitive evidence to date that smoking during pregnancy is associated with schizophrenia, they said.
Heavy maternal nicotine exposure was associated with a 38 per cent increased odds of schizophrenia, researchers said.
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Heavy smoking based on cotinine, a reliable marker of nicotine in maternal sera, was reported by 20 per cent of the mothers of cases, but only 14.7 per cent of the mothers of controls, researchers said.
Smoking during pregnancy is known to contribute to significant problems in utero and following birth, including low birth weight and attentional difficulties, they said.
Nicotine readily crosses the placenta into the foetal bloodstream, specifically targets foetal brain development, causing short- and long-term changes in cognition, and potentially contributes to other neurodevelopmental abnormalities, researchers said.
The findings were published in the journal American Journal of Psychiatry.