Women who are in the second month of pregnancy when exposed to psychological stress in a war zone or other extreme traumatic events are significantly more likely to give birth to children who eventually develop schizophrenia, according to a just-published New York University School of Medicine study of babies born in Jerusalem seven months after the Six Day War. The mental disorder, found in 1 percent of Israelis, is characterized by paranoid or bizarre delusions, abnormalities in the perception or expression of reality, auditory hallucinations, or disorganized speech and thinking. It typically appears in young adulthood. No single organic cause has been discovered, but genetics, early environment, neurobiological, psychological and social processes are believed to be important contributory factors. It is treated with medications, but there is no cure. The study was published on Thursday morning in the on-line, open-access and peer-reviewed medical journal BMC Psychiatry Research of the BioMed Central Publishing House (www.biomedcental.com). It supports a growing body of medical studies that have found that exposure of pregnant women to severe stress during pregnancy puts their children at higher risk for psychiatric illnesses such as schizophrenia. Low birthweight and premature birth have previously been shown to have some effect on the development of schizophrenia. However, the authors - NYU psychiatrists Dolores Malaspina, Anita Steckler and Joseph Steckler - stress that pregnant women should "not be alarmed about handling daily stressors during pregnancy. A developing fetus requires some exposure to maternal stress, as it normalizes their stress functioning. But women experiencing anxiety or excessive stress would do well to address it before a planned pregnancy and to have good social support systems." The NYU team suggest that not only being in a war but also being the victim of an earthquake, hurricane, terrorist attack or sudden bereavement could have the same effect as a war zone. The study is based on data from 88,829 Jerusalemites born in the capital between 1964 to 1976 that were collected from the Jerusalem Perinatal Study; it linked birth records to Israel's Psychiatric Registry. The offspring of women who were in their second month of pregnancy during the height of the 1967 war, which endangered many lives in the capital, had a significantly higher incidence of schizophrenia over the following 21 to 33 years. Girls born during the war were 4.3 times more likely than those born at other times to develop schizophrenia as adults, while boys were only 1.2 times more likely to do so. "It's a very striking confirmation of something that has been suspected for quite some time," said Malaspina. "The placenta is very sensitive to stress hormones in the mother. These hormones were probably amplified during the time of the war." The authors said their study "only supports but does not prove" their hypothesis that the greatest vulnerability to schizophrenia is during the mother's second month of pregnancy. This, they explained, is because the study is based on a relatively small population of schizophrenia patients and "the lack of data on the exact length of gestation, which makes it possible that developmental stages were underestimated." Prof. Avi Weizman, a senior psychiatrist at the Geha Mental Health Center in Petah Tikva, told The Jerusalem Post that the research was "a very interesting study that confirms previous reports of an excess incidence of schizophrenia in offspring born to mothers who experienced stress in early pregnancy. It suggests a relatively narrow window of vulnerability in the second month" and that the stress may affect early neurodevelopment that will result later in schizophrenia. "It deserves to be replicated in a larger sample," Weizman said. Prof. Arieh Shalev, the chief of psychiatry at Hadassah University Medical Center in Jerusalem's Ein Kerem, knows and respects the researchers. "Even if the increased risk of schizophrenia is a few times higher, it is still very low; it can still mean a small minority. Women should not be frightened. Severe stress in pregnant women during the Yom Kippur War, the Lebanon wars and the intifada should also be studied to see if there is support for their hypothesis," Shalev said. Dr. Danny Brom, a psychologist and director of the Temmy and Albert Latner Israel Center for the Treatment of Psychotrauma at Jerusalem's Herzog Hospital, said, "The study is important. the authors are clearly on to something, but what is really still missing is a subjective perception of the stress by the mothers. One of the most important effects of stress/trauma happens when the person experiences severe helplessness and horror. The study, therefore, as the authors suggest, creates a hypothesis but not proof. This is an interesting direction, but the evidence so far is not very convincing evidence. Although they state that mothers should not be worried, I think that their article creates too much anxiety and possibly guilt feelings in parents without a stable basis for it."