Researchers have already identified several genes associated with Attention Deficit Hyperactivity Disorder and autism, writes Dick Ahlstrom
Scientists are closing in on the genetic causes of mental illness. Researchers at Trinity College Dublin are contributing to this worldwide effort by identifying the genes associated with conditions such as schizophrenia, Attention Deficit Hyperactivity Disorder (ADHD) and autism.
"There is a lot happening in the field," says Prof Michael Gill, associate professor of psychiatry and head of the department of psychiatry at Trinity. "We have identified several genes associated with ADHD," he adds.
In several weeks, Ireland will play host to a world meeting on the genetics of mental illness when the 12th World Congress on Psychiatric Genetics takes place in Dublin. Gill is chairman of the world congress, in Dublin, in October.
"Psychiatric genetics is understanding more about psychiatric illnesses by looking at the genetic aspects," explains Gill. Researchers are on the hunt for "susceptibility genes", he says, genes that may not be working properly and leave a person at higher risk of developing depression, schizophrenia and other disorders.
The research subject is comparatively new but there is great reason for hope in relation to discoveries being made in the field, he believes. The identification of genes linked to mental illness provides opportunities for early diagnosis but also the potential for new, more effective drug therapies.
The international congress will discuss the latest findings in the field, says Prof Gill. Five or six genes linked to schizophrenia have been identified in the last two years and researchers are beginning to link susceptibility genes with environmental impacts such as stress that can join to trigger illness.
"It has become apparent that both genes and environment are at play in causing these illnesses," Gill explains. The susceptibility genes increase the risk but do not necessarily cause the illness. The research has moved on from identifying single gene illnesses such as Huntington's disease, he said. A complex mix of genes and environmental factors that act together to bring about a disease state cause the majority of these conditions.
The impact of these diseases is startling, says Prof Gill. Depression for example ranks in the top two or three on the World Health Organisation's list for a disease's influence on society. "These cause more morbidity if not mortality than heart disease and other common conditions," he says.
Researchers still struggle to understand these complex conditions. "We know very little about what causes depression, autism and ADHD. We have very little understanding of the psychobiology of these diseases."
And yet ADHaffects between 1 and 5 per cent of all school-going children, the figures varying depending on the definition you use for the disorder, says Gill. His team has identified a number of genes associated with the trait, which has received widespread media coverage in recent years. Children with ADHD find it difficult to control their behaviour or pay attention during class.
While much of the congress in October will be for specialists, Gill and his team have organised a free public session that takes place on Saturday, October 9th in Trinity College. Speakers will explain what genes are and what they do, the nature of neurological disorders will be discussed and there will be a talk explaining the basics of psychiatric genetics.
The 12th World Congress on Psychiatric Genetics takes place at the Burlington Hotel, Dublin, October 9-13th. Further information is available from the Congress website www.wcpg2004.ie