'Suicide Test' May Aid Antidepressant Decision Making

Megan Brooks

January 15, 2014

A genetic test in development promises to help doctors identify patients at increased risk for suicide after starting antidepressant therapy.

The test for treatment-emergent suicidal ideation is based on research carried out at the Max Planck Institute of Psychiatry in Munich, Germany, and published in 2011 in the journal Neuropsychopharmacology.

"We performed a genome-wide association study with depressed inpatients and compared patients who developed new suicidal ideation (which was not present at the start of the treatment) with patients who did not experience suicidal ideation," Andreas Menke, MD, coleader of the research with Elisabeth Binder, MD, PhD, told Medscape Medical News.

The researchers identified 79 single nucleotide polymorphisms associated with suicidality in new users of antidepressant medication.

"We then analyzed this subset of markers in a second, independent sample of depressed patients and found we could replicate our first finding in terms of a good discrimination of affected vs unaffected patients, with a correct classification rate of more than 90%," Dr. Menke said.

Overall, about 8% of patients developed antidepressant-induced suicidality, and nearly 59% did so within 2 weeks of beginning treatment.

Sundance Diagnostics of Boulder, Colorado, has entered into an exclusive licensing agreement with the Max Planck Institute of Psychiatry to commercialize a genetic test for treatment-emergent suicidal ideation on the basis of genetic markers that have been identified.

The company says it plans to launch the test this year as a laboratory developed assay in the United States and Europe. In addition, they plan to initiate clinical studies to validate the Max Planck results, in support of a US Food and Drug Administration submission for marketing clearance and insurance reimbursement.

"There are not many big pharmacogenetic samples which are characterized adequately to detect treatment-emergent suicidal ideation. That is why it is so important that Sundance Diagnostics initiates a prospective study to replicate our findings in a third independent sample of depressed outpatients," said Dr. Menke.

A statement from Sundance notes that roughly 11% of Americans aged 12 years and older are on antidepressant drug therapy and that the use of antidepressants increased 400% from the period 1988 to 1994 through 2005 to 2008.

Since 2005, antidepressant drugs in the United States, Canada, and a number of European countries have carried a black box warning for risk for suicide, but it is tough to determine which patients may be at risk.

"Our hope is that the new test will assist the physician in significantly reducing the risk of these tragic results and will provide patients and families with valuable personal information to use with their doctors in planning treatment," Sundance CEO Kim Bechthold said in a statement.

Clinical Utility: Too Soon to Tell

Reached for comment, Christine Moutier, MD, chief medical officer of the American Foundation for Suicide Prevention and member of the American Psychiatric Association, told Medscape Medical News: "With regard to this genetic test, we feel it is premature to comment on its clinical utility, both because the state of clinical application of the science around this specific area is very early and also because there are specific unknowns about any linkage between medications and suicidal thinking or behaviors."

"Theoretically, though, a test that could predict in advance which medicines might cause negative side effects like suicidal ideation and increased risk for an attempt would be very useful," Dr. Moutier added.

"We have known for a while that negative side effects emerge early, thus, the importance of early and ongoing monitoring of people on medicines. We don't, however, know that there is a link between medications and completed suicides, and we also do not know which pathways might mediate any linkage between medications and suicidal thinking," she said.

Any genetic test for treatment-emergent suicidality "would need to be able to make fine distinctions between medicines, since medicines in the same class differ with regard to the side effects for a given individual. It would be important not to eliminate an entire class f medicines if it is not necessary," Dr. Moutier added.

She also emphasized that "in general, antidepressants have been very effective and relieved much suffering, yet all people who start medications need to be monitored clinically and hear from their prescribing doctor what side effects to look for and how to act if they emerge."

Dr. Menke is an inventor of the patent for which Sundance Diagnostics entered into an exclusive licensing agreement. Dr. Moutier has disclosed no relevant financial relationships.



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