The answer to the schizophrenia puzzle might lie in viruses and genes

The answer to the schizophrenia puzzle might

lie in viruses and genes.

Ongoing research at Johns Hopkins University

in Baltimore is exploring the possibility that a viral infection during pregnancy could be

behind 30% to 50% of the nation’s schizophrenic cases.

Researchers have studied 100 blood samples

collected from women who gave birth in the late 1950s and early 1960s, says Robert Yolken,

professor of developmental neurovirology.  Scientists identified 35 of those mothers

whose children developed schizophrenia.  Yolken says some children may be predisposed

to a latent virus, yet to be identified, contracted by the mother.  The viral

infection is not likely to cause a problem unless the child has a genetic susceptibility

to developing schizophrenia.

Scientists now know only that there is a

gene-virus interaction.  They still have to determine whether the virus triggers

genetic activity or whether the gene is allowing the virus to replicate.

Yolken says environmental factors, such as

an infection contracted by the child later in life or malnutrition, can work in concert

with genetics to lead to the symptoms of schizophrenia.  He says there is a

possibility that the latent virus activates the immune system, triggering the onset of

that virus. Identifying the virus and its behavior could prevent cases of schizophrenia.

The trick for scientists is to isolate the

genes that can cause schizophrenia, says Ann Pulver, associate professor of psychiatry at

the university’s medical school.  That’s no easy task.  The human genome, the

set of 46 chromosomes, contains more than 80,000 genes.  The other challenge is to

isolate specific environmental factors.

Because of the genetic factor, Pulver says,

some scientists are encouraging more families afflicted by the disorder to participate in

research.  Understanding how genes are involved could at least allow researchers to

tailor medication according to specific patient needs, she says.

Referring to the Johns Hopkins research,

Henry Nasrallah, professor of psychiatry and neurology at the University of Mississippi

School of Medicine in Jackson, says the causes of schizophrenia seem to originate during

the second trimester of fetal life.  He cautions, though, that genetics is only one

avenue to explore.  Drug or alcohol abuse, trauma, accidents or organ damage

experienced by the mother also could play a significant part in determining who develops

the disorder, he says.