Tests show that a fifth of mothers of schizophrenia patients had smoked heavily while pregnant, compared with 14.7% of other mums.
Smoking during pregnancy can increase the chance of a baby having schizophrenia by 38%, according to a study.
The research from Finland found that the risk to a baby increases with the amount of nicotine a woman is exposed to during her pregnancy.
Scientists looked at data for 1,000 schizophrenia patients, matching their birth and health records with those of non-affected people.
The also examined the level of nicotine marker cotinine that was in the blood, using blood tests during the first and early second trimesters of pregnancy.
Nicotine is known to cross the placenta and enter the foetal bloodstream and can lead to development problems in babies.
The tests showed that a fifth of mothers of schizophrenia patients were found to have smoked heavily while carrying their children, compared with 14.7% of the other mothers.
Senior researcher Professor Alan Brown, from the University of Columbia in the US, said the report showed that more education was needed on the "potentially debilitating - and largely preventable - consequences that smoking may have on children over time".
He added: "Future studies on maternal smoking and other environmental, genetic and epigenetic factors - as well as animal models - should allow identification of the biological mechanisms responsible for these associations.
"Finally, it is of interest to examine maternal cotinine in relation to bipolar disorder, autism and other psychiatric disorders."
The same team has previously done research to show that children have a higher risk of developing bipolar disorder if their mother smoked while pregnant.