According to a recent study by researchers at the UC-San Francisco and Stanford on autism in twins, environmental factors are more predictive of autism risk than genetic factors. The study found that environmental factors make up 62 percent of the risk of autism while genetics, originaly thought to have been 90 percent, make up 38 percent.

The study was published in the Archives of General Psychiatry and was called the “largest, and the most diverse [study] to look at twins” by The San Francisco Chronicle. The study included 192 twins, both fraternal and identical. The rate of identical twins with dual autism was shown to be lower than predicted, and the rate of fraternal twins with dual autism was higher.

Another study examining 298 autistic children in the Kaiser Permanente Northern California system and published in the same issue showed that the risk for autism doubles with the use of antidepressants in pregnant women. With autism rates estimated at one percent of the children in the United States, scientists are hoping these findings will help expand research of the disorder.

— Haelin Cho