Brain scans could be used to predict the onset of schizophrenia in young people with a family history of the disease, a new study suggests.
An Edinburgh University study has shown people who later develop schizophrenia suffer from an accelerated brain shrinking before they become unwell.
Schizophrenia is a condition involving delusions and hallucinations.
It is associated with a reduction in brain tissue but the timing of these changes has, until now, been unclear.
Schizophrenia affects one in every 100 people.
The study examined people at high risk of schizophrenia who had two close relatives with the disorder and were between 16 and 25 at the beginning of the research.
This is the first time such changes in the brain size have been found in people at high risk of schizophrenia before they develop any symptoms.
Unlike previous studies, the changes cannot be due to medication as all of the people in the study were un-medicated when they took part.
In healthy people, the brain begins to shrink from early adulthood onwards.
It is known that accelerated brain shrinkage occurs in people with bipolar disorder, or manic-depression, and schizophrenia, but until now it was not known whether these changes occurred before people became unwell.
Researchers said scans could be used to identify shrinkage of the brain in people at high risk of schizophrenia and may help doctors to diagnose the condition and start treatment at an earlier stage or even before illness first appears.
The study, published in the journal Biological Psychiatry, shows the loss of brain tissue is concentrated in areas of the brain that control personality, decision making and social behaviour.
Dr. Andrew McIntosh, at Edinburgh University's division of psychiatry, said: "This study represents the culmination of more than 10 years of work and is a significant step to understanding the origins of schizophrenia years before the onset of disability and medical treatment."
The team analysed brain scans of 146 people with a family history of schizophrenia but who had not yet experienced any symptoms and compared them with scans of 36 people with no such risk.
The scans were taken every 18 months over a 10 year period.