February 4, 2008
Concerns Over Online Genetic Tests
A few months from now, new genetic tests will be available over the Internet that will allow people to find out, through sending off a saliva sample, if they possess a genetic variability that increases their risk of bipolar depression or schizophrenia.
The tests are based on recent discoveries of gene variants that can increase a person's chance of depression or schizophrenia. Each gene variant raises a person's risks by only a small amount, but if tests for several variants are combined it creates a useful risk assessment for an individual, according to firms such as NeuroMark in Colorado, Psynomics in California, and SureGene in Kentucky, who are marketing the tests. The tests will sell for several hundred dollars.
However, leading British psychiatrists have been highly critical of the online availability of these tests, claiming the technology is still nascent and cannot yet help in making diagnoses. They also warn the online tests might even worsen individuals' mental and emotional problems.
"These tests will only worry, confuse and mislead the public and patients," said psychiatrist Professor Nick Craddock of Cardiff University in a statement to the British publication The Guardian. "There is a long way to go before we have genetic tests that may be helpful to patients. Using tests at the moment is only likely to cause harm."
Professor David Collier of the Institute of Psychiatry, London, agreed with Craddock. "At best, these tests are clinically useless. At worst, their results could cause serious worries for patients," he said.
For example, Psynomics has developed a test for identifying individuals at risk for depression. The company's chief executive John Kelsoe told Science magazine last week, "This is going to be initially driven by patients."
But Dr. Cathryn Lewis of the Institute of Psychiatry in London disputed the usefulness of these tests. "The general risk of developing bipolar depression is around one per cent. If you possess the worst set of gene variants, then your risk rises to three per cent. That means you are three times more likely than average to get bipolar depression. That may seem worrying but it is still a very low risk. It is still 97 per cent likely that you won't get depression. People are not likely to realize that."
According to the Guardian, another test to be sold by NeuroMark, first in the US and later this year in Europe, is based on genes that predispose people to react badly to stress. If a person inherits this gene section from both parents, he or she has an increased chance of suffering from severe depression after stressful situations. 'About 20 per cent of people have this combination,' said Kim Bechthold, NeuroMark's chief executive officer. "It is useful information to know."
Bechthold recommends those who test positive for these variants could then take actions to counter their risks. "We suggest joining a choir, eating chocolate or buying a puppy," she told the Guardian.
Craddock dismissed the idea. "Life is stressful. You cannot avoid it. It is extremely unhelpful to tell people that they face a risk like that."
Complicating the issue even further is that scientists have found only a small number of risk gene variants for psychiatric disorders. It is thought many more exist but have not yet been discovered.
"The trouble is that if someone takes a test which suggests they face no risk, they could easily think they can then do what they want," Craddock said.
"They might start taking recreational drugs again, which would pose problems if they are prone to depression. Other risk gene variants might later be discovered and new tests developed. Then we will find these people actually have an inherent proneness to depression after all. It will be too late by then, however."
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