In an update to a recent study, researchers say they are continuing to find evidence that women who take supplements containing choline when they're pregnant may lower the risk of schizophrenia in their children.

The children in the study are now 4 years old, and are already showing fewer early signs of schizophrenia — such as certain attention and social problems — than expected, said Dr. Robert Freedman at a talk in New York City on Oct. 23.  Half of the children in the study had an increased risk for schizophrenia because their mothers had depression, anxiety or psychosis.

Freedman, the chairman of the department of psychiatry at the University of Colorado School of Medicine and editor in chief of The American Journal of Psychiatry, gave attendees at the Brain and Behavior Research Foundation symposium an update on the participants in his study, which was originally published in 2013 in The American Journal of Psychiatry.

In the 2013 study, Freedman and his team looked at the brains of the babies when they were newborns.  They found that those whose mothers took a supplement containing phosphatidylcholine (a version of the nutrient choline) during the second or third trimester of pregnancy showed improvements in how well nerve cells could block certain signals, compared to a group whose moms were given a placebo. In people with schizophrenia, this ability to block these signals does not fully develop.

This means that people with schizophrenia are unable to block out certain sensory signals, making it difficult to focus their attention, Freedman said at the research meeting last month.

Schizophrenia — which affects about 1 percent of American adults — is characterized by an inability to distinguish some aspects of reality from the imagination, Freedman told Live Science. People with the condition may hear voices that aren't there, hallucinate and have delusions, he said. And they are less able to function in their daily lives, he said. [Schizophrenia: Symptoms and Treatments]

However, because the symptoms of schizophrenia usually don't become apparent until late adolescence or early adulthood, studying the disease in infants and children is challenging, he said.

To do so, Freedman and his team turned their attention to neurons in infants' brains. In the study, the researchers played clicking sounds for the babies, and measured how well the infants' brain inhibited certain signals. 

In infants whose mothers had taken the choline supplement, the researchers observed more signal inhibition than those whose mothers had taken a placebo, Freedman said at the meeting.

Choline's potential

It isn't clear whether choline may actually lower children's risk of developing schizophrenia later in life; much more research is needed to look at the question. But research has shown that choline turns on receptors in the brain that help promote the development of inhibitory nerve cells.

Many people with schizophrenia — and other mental illnesses as well — have fewer of these receptors to begin with, due to genetics, Freedman said. That means these people could benefit from making sure all of the receptors that are present are turned on, Freedman said.

Choline is necessary for other reasons too, during the development of a fetus, because it is used to make cell membranes, the researchers wrote in their study. However, higher levels than those that are usually recommended are needed to turn on the receptors, they wrote. The current recommended dosage for pregnant women is 450 milligrams of choline daily, according to the National Institutes of Health; foods that are rich in choline include egg yolks, meat and soybeans.

Four years later, the newborns whose moms took choline in the study are already doing better, Freedman said. Those whose moms took choline are less likely to have problems with attention and social interactions, he said. People with schizophrenia often have problems in these two areas as children.

Still, because the typical age at which schizophrenia begins is still many years off — and because the number of children in the study is low — researchers won't have a definitive answer for some time.

Even without final results, Freedman said he believes that all women (and by implication, their children) could benefit from taking choline during pregnancy.

There are no risks to women at the doses we're recommending, Freedman told Live Science.  In the study, the women took the equivalent of 900 milligrams of choline daily. He did note, however, that if women take much more of the nutrient, they could have some problems digesting it.

Still, Freedman stressed that women should always check with their obstetrician before taking any nutritional supplement.

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