Scientists have identified three genes that could play a role in causing schizophrenia, a German researcher said.

"After 10 years without any real success, we have now determined three candidate genes," Germany's Saarland University Professor Peter Falkai said.

Professor Falkai said the genes Dysbindin, Neuregulin and G72 had been identified but that anywhere from 50 to 100 genes could be involved in causing schizophrenia.

Speaking at a conference of the German Research Network on Schizophrenia, a government healthcare research program, Professor Falkai said the findings were made by several working groups, with German scientists playing a significant role.

He said about half the cases of schizophrenia, which usually manifests itself during late adolescence or early adulthood, were probably caused by the genes with the other half due to environmental triggers.

Those could include complications at birth or during pregnancy, viral illnesses, hashish consumption and high stress levels in cities.

University of Bonn professor Wolfgang Maier described the progress made on the disease, which hits about one in 50 people, as a "crucial breakthrough".

While findings suggested that medicine currently used to treat schizophrenia was relatively effective, the gene findings could lead to new treatments.

"Instead of symptomatic therapy, we now have the chance to develop a selective causal therapy," Professor Falkai said.

http://www.abc.net.au/news/newsitems/s973351.htm