Brain scans reveal risk of psychosis
29 October 2006
Brain scans of young people at risk of schizophrenia have allowed researchers to link a gene variation to likelihood of developing symptoms. The variation has been found in a gene called neuregulin. The results provide an insight into how a specific gene can generate changes in brain activity and signal a person’s risk of developing psychotic symptoms.
The research team at the University of Edinburgh compared the DNA and the functional magnetic imaging (fMRI) brain scans, from young people at risk of schizophrenia. This allowed them to link the gene variant to the abnormal beliefs and voices people who have schizophrenia can experience. The research is published online in Nature Neuroscience.
The research is part of the Edinburgh High Risk Study funded by the Medical Research Council. The study followed 200 young people at risk of developing schizophrenia for 10 years.
Schizophrenia is known to have a strong inherited element and symptoms usually first appear between the ages of 16 – 28. People in the Edinburgh study were at high risk of developing the illness because two or more members of their family already suffered from the condition.
Over the course of the study participants had regular fMRI brain scans, clinical interviews and psychological tests. More recently participants also gave blood for genetic analysis. They were then grouped together according to the version of the neuregulin gene their DNA revealed they carried.
Study participants were asked to complete a sentence whilst having an fMRI scan. This task was designed to activate the frontal and temporal regions of the brain, which are also known to be affected in schizophrenia.
Professor Eve Johnstone, of the Royal Edinburgh Hospital, praised the young people who took part in the study:
‘‘We were only able to gather these exciting results because of the outstanding collaboration we have with the young people in the study. Both those at risk and the people who took part as controls co-operated in our investigations for years. They knew that it would not help them but might in the long run help others. Some of them were facing the fact that they might be developing the illness that they had seen in other people in their own family. I cannot speak highly enough of their altruism and courage.”
The researchers found that there was a link between one particular variation of the neuregulin gene and risk of developing psychotic symptoms. They achieved this by first looking for psychotic symptoms in the genetically different groups of people. They found that people who carry a version of the neuregulin gene, known as T/T, were much more likely to develop symptoms. Later examination of the brain scans showed that this same group of people also had abnormal activity in their frontal and temporal brain regions. This suggests that people who have the T/T version of the neuregulin gene have changes in brain function that make them more likely to develop psychosis than people who don’t.
Dr Jeremy Hall of the Division of Psychiatry at the University of Edinburgh explains:
“These results help us understand more about how genes alter brain function in psychosis. Hopefully increasing knowledge in this area will make it possible to develop new treatments in the future.”
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psychotic symptoms is published online in Nature Neuroscience on 29th
October 2006.
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