NEW YORK, Feb 09 (Reuters Health) -- People who experienced a reduced
oxygen supply either before or at birth, or who were born after a long and
complicated labor, may be at higher risk for developing schizophrenia than those
who did not experience such traumas, two new reports indicate.
In one study of nearly 700 people born between 1959 and 1966, about 6% of
those who suffered from a reduced oxygen supply either before or at birth
developed schizophrenia. In comparison, only 0.39% of people without such
complications developed the psychiatric illness, according to the report in the
February issue of the American Journal of Psychiatry.
Birth complications may be an environmental trigger that promotes
schizophrenia in a person with a genetic disposition to the mental illness,
conclude study co-author Dr. Gwen L. Zornberg, of the Harvard School of Public
Health in Boston, Massachusetts, and colleagues.
More research is needed to focus on the link between the reduction of
oxygen supply to the fetus and later brain structure and function, suggest the
researchers.
Schizophrenia usually develops in teens or young adults, more often among
men than women, and is characterized by hallucinations, withdrawal from social
interaction, and problems with language and communication. The cause of the
disease in unknown, but it is more common in those with relatives with the
mental illness.
In a second study in the same journal, Swedish and American researchers
studied 22 sets of twins in which one of the siblings had schizophrenia and one
did not. Using magnetic resonance imaging, they found that the schizophrenic
twins consistently had differences in the size of certain parts of their brain,
according to the study.
The differences in brain region were associated with labor-delivery
complications, such as prolonged labor, according to Dr. Thomas F. McNeil of
Lund University in Malmo, Sweden, and colleagues. The authors suggest that the
twins may have actually received different exposures to the same complication or
developed in different ways because of other unknown influences.
Future research is needed to determine what environmental factors caused
the differences, the researchers conclude.
