Neuroscientist Saw Wang, writing for the New York Times, tries to make some sense out the the science surrounding autism spectrum disorders. He’s particularly interested in the risk factors that are linked to rises in autism. Along the way he compared the risks discovered in scientific studies to the risks reported by the media:
(click twice to embiggen. Or go to the original article)That last entry is pretty striking. There is no evidence currently that vaccines increase the risk of autism, but it receives more attention than any other factor. Wang seems particularly interested in one of the under-reported factors:
A highly underappreciated prenatal risk is stress. For pregnant women who take the sometimes-wrenching step of emigrating to a new country, for example, the risk ratio is 2.3. In the fifth through ninth months of pregnancy, getting caught in a hurricane strike zone carries a risk ratio of about 3. Maternal post-traumatic stress disorder during pregnancy is associated with a similar effect. These events are likely to trigger the secretion of stress hormones, which can enter the fetus’s bloodstream and affect the developing brain for a lifetime. Stressors may also lead to maternal illness, the immune response to which may interfere with brain development.