A team of medical scientists at Trinity College Dublin have identified a rare genetic mutation, which increases the risk of developing schizophrenia or bipolar disorder more than tenfold.
The study examined blood samples from over 1,500 Irish people with schizophrenia and over 1,700 people without, for variations where genetic material was duplicated, or deleted.
Once the genetic mutation was identified in Irish cases, the team checked for the mutation in a larger European sample of over 25,000 people.
This confirmed that the genetic duplication, while rare, increased the risk of developing schizophrenia or bipolar disorder more than tenfold.
Dr Aiden Corvin, Professor in Psychiatry at the TCD school of medicine, said progress in understanding the molecular mechanisms of disease gives hope that new effective treatments will emerge.
The next steps will be to understand how this duplication interferes with brain cell function and to test how it might be reversed.
Prof Corvin said that treatment in the area of schizophrenia or bipolar disorder had advanced little in the last 40 years.
Schizophrenia or bipolar disorder affects around one in 50 Irish adults.
The study was funded by the Wellcome Trust and Science Foundation Ireland and included collaborations from experts in Europe and the US.