Dr. Judith Rapoport, chief of the National Institute of Mental Health's child psychiatry branch, answers questions about childhood schizophrenia.
Dr. Judith Rapoport: We've been studying childhood onset schizophrenia for the past 20 years, it is very rare. It's only 1/300th of 1 percent of the rate for the adults.
So we know that it's really very rare, but we think that it's really important because when the diseases start in childhood, often they have much stronger genetic effects. You can understand the biology because it's a stronger effect.
Q: What causes schizophrenia?
JR: There is a lot of information on risks for schizophrenia, generally, that includes children and adults. It's a bewildering array, suggesting that first of all, it's in part genetic, but only part. Identical twins are only both ill in a little less than half the cases, and since they have the same genes, that means you need something else in order to have the disorder.
Then, in addition to that, there are studies of pregnancy that suggest that if you have some problems like infections early in pregnancy, you may have a higher rate. ... There are other studies that show that children with certain developmental delays and speech and language [problems] have a higher risk for later, when they get to be adults, having schizophrenia.
And there are other studies that suggest living in cities as opposed to the country increase your risk. Part of the problem is that there's been a lot of very excellent research, and it's harder to know how to put all this together.