Viruses and genes interact in a way that may increase the risk of developing schizophrenia significantly - even in a developing fetus, according to an international team which scanned the genomes of hundreds of sick and healthy people to see if there is an interaction between genes and a very common virus, cytomegalovirus, and to see whether the interaction influences the risk of developing schizophrenia.
And it does, they concluded.
Women who have been infected by the virus - around 70 % have - will see a statistically significant increased risk of giving birth to a child who later develops schizophrenia if the child also has the gene variant. This variant is found in 15 percent.
The risk is five times higher than usual.