Scientists have discovered new clues to the causes of autism after studying twins.
The researchers looked at 192 sets of twins where at least one twin was autistic. They found that there were high rates of both twins being autistic in identical twins (77% in boys, 50% in girls).
But the researchers also discovered that 31% of non-identical boy twins and 36% of non-identical girl twins were both autistic. This is much higher than previously thought, and suggests that environmental factors during pregnancy may be an important factor.
It’s not yet known what these factors might be, but some suggestions include stress or illness during pregnancy, ages of the parents, or medicines such as antidepressants taken during the pregnancy.
A second study published this week showed that mums-to-be who took antidepressants during pregnancy (particularly in the first three months) were slightly more likely to have an autistic child.
However, the risk still remains very small and researchers urged pregnant women not to immediately stop taking antidepressants. Instead, if you are concerned you should talk to your doctor.
Scientists have already established that there can be a genetic link with autism. It’s thought that a genetic susceptibility to autism may combine with environmental factors to make the development of the condition more likely. The hunt is now on to find what those factors may be.