Genetic Testing for Psychiatric Diseases

by Dr. Hsien-Hsien Lei
Posted February 6, 2008 in DNA Testing, DNA and Disease

Three companies–Neuromark, Psynomics, and SureGene–are joining the genetic testing fray. Each is offering genetic tests for variants associated with mental illness.

• Neuromark’s Mark-C test is undergoing confirmatory studies (according to the website). The test will examine two genetic markers, GRIK2 and GRIA3, that appear to increase the risk of suicidal thoughts in people taking antidepressant drug Celexa.
• Psynomics claims to be the “first and only” company in the world to offer DNA tests for mental illness. Psynome tests for two mutations in the GRK3 gene associated with bipolar disorder. Psynome2 tests for mutations in the Promoter L allele gene that are associated with response to serotonin-based drugs.
• SureGene has developed the AssureGene test that examines a panel of (unspecified) genes and markers that is being marketed to aid in the diagnosis of patients at risk of developing psychosis. The test may also be used to predict drug response to antipsychotic medications.

Not surprisingly, the genetic tests have met with skepticism. Dr Cathryn Lewis at the Institute of Psychiatry, London was quoted in Guardian:

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 realise that, however.

Without seeing the reports issued by these companies and not knowing whether genetic counselors are available by phone or email, I can’t say for sure that these companies are not providing proper customer service and information. At this early stage of genetic testing, however, potential consumers who have done their homework and studied their family medical history may find that these tests provide a tip-off towards more careful follow-up.

Family practice physician Tim Janzen wrote the following in a GENEALOGY-DNA list discussion (reprinted with permission):

I think that those in the medical profession are going to have positions all over the map on this topic. Some will be afraid that the results of genetic tests will cause unnecessary anxiety among those who are tested and shown to be predisposed to certain diseases. I fully admit that it may do that for at least some people. Others will welcome the information in that it will hopefully allow the doctors to be better informed as to which of their patients are at higher risk for mental illness.

I wouldn’t be surprised if the results of genetic tests are eventually integrated into treatment algorithms for people with mental illness. For instance, if a patient presents with depression and the genetic tests indicate a strong predisposition to depression, the doctor may be more inclined to treat that patient for many years with an antidepressant rather than just the 6 month minimum that is generally recommended for patients who present with depression for the first time.

The medical profession will simply need to keep in mind that these genetic tests will show predispositions to certain diseases, but a predisposition is frequently not equivalent to being destined to have the disease. We already welcome information such as cholesterol levels and blood pressure readings that tell us which patients are predisposed to heart disease and stroke. We act on those results accordingly.

Patients who have a family history of mental illness or other conditions already know that they have a predisposition (unless they are adopted). Thus the genetic results will either reinforce the fact that specific patients are at increased personal risk or they will show that they are at lower risk than they might otherwise be. We shouldn’t forget that environment also plays a role in mental health. Drug abuse is one environmental factor that also predisposes to mental illness.

For more about mental health, visit Alicia Spark’s Mental Health Notes.

NB: Andro Hsu of 23andMe has made a similar point in the past about presenting risk information.

(HT: UCL Institute of Human Genetics and Health)

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Comment by Alicia Sparks, NAMI Affiliation Leader

2008-02-06 18:26:15

I was nodding in agreement with everything Tim Janzen said, especially “I wouldn’t be surprised if the results of genetic tests are eventually integrated into treatment algorithms for people with mental illness.”

We’ve talked about this some at our last few NAMI meetings, and the general consensus (at those meetings, which is only representative of a few NAMI employees and mental health consumers in the area) is excitement over the prospect of being able to get more specialized treatment.

Great post!

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Pingback by Double The Sanity This Saturday!

2008-02-09 10:06:15

[...] King sent me a great tip: Genetic Testing for Psychiatric Diseases – turns out, the very organized Dr. Hsien-Hsien Lei has outlined how three companies are involved [...]

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Pingback by Psychiatric Genetics

2008-06-20 04:26:22

[...] some more information about genetic tests and psychiatric disorders: In a recent post on Eye on DNA by Dr. Hsien Hsien Lei, describes newly-developed (and, in some cases, still being developed) [...]

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