by Barbara Boughton
June 14, 2012 — High levels of maternal antibodies to gluten in pregnant women may be linked to the development of nonaffective psychosis in their children in later life.
Investigators from the Karolinksa Institute, in Stockholm, Sweden, found that levels of immunoglobulin G (IgG) higher than the 90th percentile in the maternal circulation were associated with nonaffective psychosis in offspring in adulthood.
“To our knowledge, this is the first study to show an association between high levels of maternal antibodies directed at gliadin [a component of gluten] and the later development of nonaffective psychosis,” the researchers, led by Håkan Karlsson, PhD, write.
The study is published in the June issue of the American Journal of Psychiatry.
Previous studies have linked maternal malnutrition or infections with development of schizophrenia and other nonaffective psychoses.
Also, other studies have shown immune activation at the time of the first symptoms of nonaffective psychosis, the investigators note.
However, the current study is the first to assess whether antibodies to dietary antigens in blood samples taken from mothers at birth might be linked to the development of nonaffective psychosis in adult offspring.
Although the findings raise interesting questions, its data are preliminary and should not be considered proof of a link between gluten sensitivity in mothers and psychosis in children, one expert said.
“My concern is that there is a big epidemic of anxiety about gluten right now,” said Nada Stotland, MD, MPH, past president of American Psychiatric Association and professor of psychiatry at Rush Medical College, in Chicago, Illinois, in an interview with Medscape Psychiatry.
“I’m very concerned about any information that might cause frenzy among pregnant women who are already worried about environmental and dietary factors affecting their children,” Dr. Stotland said.
Another Piece of the Puzzle
In the study, researchers analyzed the presence of antibodies to dietary antigens in blood samples collected from pregnant women who gave birth between 1975 and 1985 in Sweden.
The levels of antibodies to dietary antigens in birth mothers’ blood were compared for 211 participants with nonaffective psychosis to such levels in 553 people without mental illness.
The participants were treated in hospitals or as outpatients in Sweden between 1987 and 2003; the 553 control participants were selected from a population-based medical birth registry in Sweden. Blood samples from birth mothers collected for the same birth registry were used for the analyses.
Results indicated that high levels of IgG antigliadin antibodies from the birth mothers were associated with a significantly elevated risk for nonaffective psychoses in their offspring.
The researchers also assessed the presence of antibodies to casein, an ingredient in milk, in the mothers’ blood — but they did not find a significant association with the development of nonaffective psychosis in offspring (odds ratio [OR], .8; 95% confidence interval [CI], .4 – 1.5).
“This is exciting research because every piece of the puzzle that leads to our understanding of psychosis is welcome. These are important questions because psychotic disorders have the potential to ruin people’s lives and stress families very severely,” Dr. Stotland said.
“Autoimmune factors and their influence on psychosis have not been studied that much,” she added.
Yet, to truly know whether dietary factors are important in the development of psychosis will take many more studies and clinical trials, she noted.
Dr. Kårlsson and Dr. Stotland have disclosed no relevant financial relationships.
Am J Psychiatry. 2012;169:625-632. Abstract