Prenatal lead exposure linked to schizophrenia
10:26 16 February 04 NewScientist.com news service Exposure to lead while in the womb may double a
child's risk of developing schizophrenia later in life, new research suggests.
While larger studies are needed to confirm the link, the researchers say this is the first time an
environmental toxin has been linked to the disorder.
Ezra Susser and his colleagues at Columbia University in New York followed 12,000 children born in
Oakland, California, between 1959 and 1966. Lead was still routinely used in petrol at that time.
Their mothers had given samples of blood serum while they were pregnant, which were frozen and
stored for later analysis.
Susser's team studied the medical records of the children later in life, and tracked down 44 who
were diagnosed with schizophrenia or a related disorder. They then compared the levels of lead in
the blood of mothers whose children developed schizophrenia with those who did not.
They found that children who had been exposed to high levels of lead in the womb were more than
twice as likely to go on to develop the disease. The result will be published in a future issue of
Environmental Health Perspectives.
Nerve connections
The researchers now plan to repeat the study with a larger number of children. This will not only
give them the chance to confirm that the link is real, but also to try to pin down whether there is
a specific time during pregnancy when lead exposure produces an increased risk.
Susser says the idea that lead exposure might lead to schizophrenia is compelling, because the metal
is known to inhibit brain activity in the same way as alcohol. Children who have suffered fetal
alcohol syndrome have neurological problems as the result of nerve cells in the developing brain not
forming vital connections.
If it is proved that lead triggers schizophrenia in this way, it would be the first firm explanation
for how an effect in the womb can lead to the illness.
"If we can understand even one pathway of how schizophrenia is caused, we could open up the world of
schizophrenia research to treatment and prevention," says Susser.
The research was presented at the annual meeting of the American Association for the Advancement of
Science in Seattle, Washington.
Joanna Marchant, Seattle