Screening for early brain changes may predict schizophrenia, scientists have claimed. A new brain imaging study published in the American Journal of Psychiatry (2000;157(111);1829-34) shows that there are substantial brain changes in schizophrenia at the earliest stages of the illness, implying that these changes pre- cede the appearance of psychotic symptoms.

The findings from the Institute of Psychiatry indicate that brain changes are evident while the illness is in its earliest stages, and the study raises the possibility of using brain imaging to prevent schizophrenia at some time in the future.

There were 68 people in the study; 37 were experiencing their first episode of psychosis and the rest were healthy volunteers. Magnetic resonance imaging (MRI) scans identified differences in the structure of key regions, such as the temporal lobe, between the healthy volunteers and those experiencing psychosis.

Dr Tonmoy Sharma, who led the study, thinks that in future brain imaging may provide a way of identifying early signs of schizophrenia and could fundamentally alter the approach to the condition. "From this study, we can see that characteristic brain differences are present at a very early stage and also shows the promise that brain imaging may become a powerful predictor of future illness."

While previous research has shown that there are differences in the brains of people with schizophrenia and healthy volunteers, these studies have often involved people who have had schizophrenia for many years. So it is difficult to identify whether brain changes are due to the ageing process, a result of the illness, or the side effects of the medication.

In the new study all the participants had experienced psychosis for only three months or less, and some had never taken antipsychotic drugs. The MRI scans showed quite distinct brain changes in key regions, suggesting that by the time someone started to show signs of psychotic behaviour, their brains were already structurally different.

Researchers are now starting to focus on the prodrome phase, the stage before psychosis becomes apparent, in an attempt to prevent schizophrenia. Dr Sharma said, "In cancer, we've seen that screening people at risk can have a great effect on treatment success. With a suit- able schizophrenia screening method, for the first time, preventive psychiatry becomes a realistic possibility.