Skip to content
My WebMD Sign In, Sign Up

Schizophrenia Health Center

Font Size

Schizophrenia Not Linked to Prenatal Exposure to Influenza


"I think this is an excellent paper. The investigators use the Danish Registry Data which has been developed over decades which is just now bearing fruit for schizophrenia research", Ezra Susser, MD, DrPH, tells WebMD. "They looked at things rarely examined in schizophrenia research: birth order, sibship size, space between siblings. As far as the small interval between siblings, you can't make too much of the findings yet but they're really intriguing."

"They tested the influenza hypothesis in a much better way than previous studies," he says. Susser, the head of the Epidemiology of Brain Disorders program at the New York State Psychiatric Institute and Columbia University, was not associated with the Westergaard research.

Other experts aren't so sure. "This study casts further doubt that influenza is an important infection in causing later cases of schizophrenia. However, I take serious exception to the conclusion that in utero infections are not important," E. Fuller Torrey, MD, tells WebMD. "Increasingly research, including our own, has shown that infections both in utero or in early childhood may well play a role in later development of both schizophrenia and bipolar disorder." Torrey, who also is not associated with the study, is from the developmental neurovirology laboratory of the Stanley Research Foundation for Research in Schizophrenia and Bipolar Disorder in Bethesda, MD.

"It's important to stress that there is no database in the world as good as the database they are using, which consists of the entire population of Denmark, to answer the kinds of questions they're asking", says Torrey. "However, the big problem with these influenza studies is that it doesn't tell you whether the mother [of the schizophrenia patient] actually had it or not. You're not going to be able to measure what's going on in utero by measuring the incidence of maternal symptoms or infections in the community." He suggests there may be women who have influenza but do not report it to the medical authorities or perhaps are asymptomatic or only mildly symptomatic.

Torrey adds, "Pregnancy is like a black box. It's conceivable that there's a whole series of things going on, including infections, and we only have the vaguest idea of what's going on. We can only measure the most extreme ends of the spectrum."

Vital Information:

  • It is unknown what causes schizophrenia, but scientific theories suggest there is a genetic component, possibly combined with an exposure to infections either in the womb or during early childhood.
  • A new study finds that having a lot of siblings, especially ones that are closely spaced, is associated with a higher risk of schizophrenia.
  • This finding adds evidence to the hypothesis than an infection during early childhood is somehow related to schizophrenia, since a family with many, close siblings will likely have more exposure to infections.

Today on WebMD

Mental Health Psychotic Disorders
Schizophrenia Medications
bored man resting chin on hands
10 Questions to Ask Doctor About Schizophrenia
brain scan
Schizophrenia What Increases Your Risk
Bipolar or Schizophrenia
male patient with doctor
romantic couple
colored pencils
businesswoman working at desk at night

WebMD Special Sections