News and events:

Schizophrenia genes increase chance of IQ loss, study shows

Schizophrenia genes increase chance of IQ loss, study shows - 21 February 2013. Comstock images © Getty Images
News from: The University of Edinburgh Centre for Cognitive Ageing and Cognitive Epidemiology

People who are at greater genetic risk of schizophrenia are more likely to see a fall in IQ as they age, even if they do not develop the condition.

Scientists at the University of Edinburgh say the findings could lead to new research into how different genes for schizophrenia affect brain function over time. They also show that genes associated with schizophrenia influence people in other important ways besides causing the illness itself.

Ian Deary leads the Lothian Birth Cohort research team. Credit: Lothian Birth Cohort research team
Ian Deary leads the Lothian Birth Cohort research team. Image: Lothian Birth Cohort research team

The researchers used the latest genetic analysis techniques to reach their conclusion on how thinking skills change with age.

They compared the IQ scores of more than 1,000 people from Edinburgh who were tested for general cognitive functions in 1947, when the subjects were aged 11, and again when they were around 70 years old.

The researchers were able to examine people's genes and calculate each subject's genetic likelihood of developing schizophrenia, even though none of the group had ever developed the illness.

They then compared the IQ scores of people with a high and low risk of developing schizophrenia. They found that there was no difference at age 11, but people with a greater genetic risk of schizophrenia had slightly lower IQs at age 70.

Those people who had more genes linked to schizophrenia also had a greater estimated fall in IQ over their lifetime than those at lower risk.

Ian Deary, Director of the University of Edinburgh's Centre for Cognitive Ageing and Cognitive Epidemiology, who led the research team, said: "Retaining our thinking skills as we grow older is important for living well and independently. If nature has loaded a person's genes towards schizophrenia, then there is a slight but detectable worsening in cognitive functions between childhood and old age."

Andrew McIntosh, of the University of Edinburgh's Centre for Clinical Brain Sciences, said: "With further research into how these genes affect the brain, it could become possible to understand how genes linked to schizophrenia affect people's cognitive functions as they age."

Schizophrenia - a severe mental disorder characterised by delusions and by hallucinations - is in part caused by genetic factors. It affects around 1 per cent of the population, often in the teenage or early adult years, and is associated with problems in mental ability and memory.

The study, which was funded by the Biotechnology and Biological sciences Research Council, Age UK, and the Chief Scientist Office, is published in the journal Biological Psychiatry.

The University of Edinburgh's Centre for Cognitive Ageing and Cognitive Epidemiology is funded by the Cross Council Lifelong Health and Wellbeing initiative.

ENDS

About BBSRC

BBSRC invests in world-class bioscience research and training on behalf of the UK public. Our aim is to further scientific knowledge, to promote economic growth, wealth and job creation and to improve quality of life in the UK and beyond.

Funded by Government, and with an annual budget of around £500M (2012-2013), we support research and training in universities and strategically funded institutes. BBSRC research and the people we fund are helping society to meet major challenges, including food security, green energy and healthier, longer lives. Our investments underpin important UK economic sectors, such as farming, food, industrial biotechnology and pharmaceuticals.

For more information about BBSRC, our science and our impact see: www.bbsrc.ac.uk .
For more information about BBSRC strategically funded institutes see: www.bbsrc.ac.uk/institutes .

External contact

Eleanor Cowie, Press and PR Office, The University of Edinburgh


Tel: 01316 56382