"Long before it's in the papers"
February 04, 2008

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Severe stress in pregnancy may be tied to kids’ schizophrenia

Feb. 4, 2008
Courtesy JAMA and Archives Journals
and World Science staff

Chil­dren of wom­en who suf­fer an ex­tremely stress­ful event—such as the death of a close rel­a­tive—dur­ing preg­nan­cy’s first tri­mes­ter ap­pear more likely to de­vel­op schiz­o­phre­nia, a study re­ports.

Past re­search al­ready bears out, some­what, “the com­mon con­cep­tion that a moth­er’s psy­cho­log­i­cal state can in­flu­ence her un­born baby,” the re­search­ers wrote in re­port­ing their find­ings.

“Se­vere life events dur­ing preg­nan­cy are con­sist­ently as­so­ci­at­ed with an el­e­vat­ed risk of low birth weight and pre­matur­ity,” con­tin­ued the sci­en­tists, Ali S. Khashan of the Un­ivers­ity of Man­ches­ter, U.K., and col­leagues. Their pa­per ap­pears in the Feb­ru­ary is­sue of the re­search jour­nal Ar­chives of Gen­er­al Psy­chi­a­try.

Schiz­o­phre­nia, a dis­abling men­tal ill­ness tied to ab­nor­mal brain struc­ture, is in­creas­ingly be­lieved to beg­in in early brain de­vel­opment, the in­ves­ti­ga­tors added. En­vi­ron­men­tal fac­tors, in­clud­ing those oc­cur­ring dur­ing preg­nan­cy, and genes may in­ter­act to in­flu­ence risk, they not­ed.

The sci­en­tists used da­ta from 1.38 mil­lion Dan­ish births from be­tween 1973 and 1995. Us­ing a na­t­ional reg­is­try, the sci­en­tists checked wheth­er any of the moth­ers’ close rel­a­tives had died or suf­fered can­cer, heart at­tack or stroke dur­ing the preg­nan­cies.

Risk of schiz­o­phre­nia and re­lat­ed dis­or­ders was about 67 per­cent high­er among off­spring of wom­en ex­posed to the death of a rel­a­tive dur­ing the first tri­mes­ter, the team found. This risk was un­af­fect­ed by deaths of rel­a­tives at any oth­er time dur­ing or shortly be­fore the preg­nan­cy, they added, and the link they found seemed sig­nif­i­cant only for peo­ple with no family his­to­ry of men­tal ill­ness.

A pos­si­ble ex­plana­t­ion for the re­sults, they said, is that chem­i­cals re­leased by the moth­er’s brain in re­sponse to stress may af­fect the fe­tus’ de­vel­oping brain, es­pe­cially early in preg­nan­cy when pro­tec­tive bar­ri­ers be­tween moth­er and fe­tus are weak.

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Children of women who suffer an extremely stressful event—such as the death of a close relative—during pregnancy’s first trimester appear more likely to develop schizophrenia, a study reports. Past research already backs up, somewhat, “the common conception that a mother’s psychological state can influence her unborn baby,” the researchers wrote in reporting their findings. “Severe life events during pregnancy are consistently associated with an elevated risk of low birth weight and prematurity,” continued the scientists, Ali S. Khashan of the University of Manchester, U.K., and colleagues. Their paper appears in the February issue of the research journal Archives of General Psychiatry. Schizophrenia, a disabling mental illness tied to abnormal brain structure, is increasingly believed to begin in early brain development, the investigators added. Environmental factors, including those occurring during pregnancy, and genes may interact to influence risk, they noted. The scientists used data from 1.38 million Danish births from between 1973 and 1995. Using a national registry, the scientists checked whether any of the mothers’ relatives had died or suffered cancer, heart attack or stroke during the mothers’ pregnancies. Risk of schizophrenia and related disorders was about 67 percent higher among offspring of women exposed to the death of a relative during the first trimester, the team found. This risk was unaffected by deaths of relatives at any other time during or shortly before the pregnancy, they added, and the link they found seemed significant only for people with no family history of mental illness. A possible explanation for the results, they said, is that chemicals released by the mother’s brain in response to stress may affect the fetus’ developing brain, especially early in pregnancy when protective barriers between the mother and fetus are weak.