Genes Might Predispose Antidepressant Users to Suicidal Thoughts

Someday, DNA tests might spot those most at risk, experts say.

By Amanda Gardner
HealthDay Reporter
Thursday, September 27, 2007; 12:00 AM

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THURSDAY, Sept. 27 (HealthDay News) -- Variations in two genes may help spur suicidal thinking in individuals taking a commonly prescribed antidepressant, research suggests.

Although preliminary, the findings could pave the way for genetic testing to determine which patients with depression are likely to have this unusual but dangerous side effect.

"These findings, if replicated, would provide a way to have a genetic test that would tell us who is at a higher risk of developing suicidal ideation when taking antidepressants," said Dr. Gonzalo Laje, lead author of the study and associate clinical investigator at the U.S. National Institute of Mental Health. "Our long-term goal is to make sure that people with depression can take antidepressants, because treating depression is the best way to avoid suicide," he said.

Other experts stressed the need for more studies before getting too excited about the finding.

"The real key is, does it replicate in another data set? . . . [because] replicating results is rare," said Dr. Michael Slifer, assistant professor of medicine at the University of Miami Institute for Human Genomics. "It's a very important topic," said Slifer, who was not involved in the study. "Nobody has really looked into what might be different about the background of these folks that have such a difficult time in treatment and get suicidal thoughts. This is a first step, but it's only a first step."

There is some evidence that people starting antidepressant medication can develop suicidal ideation, or suicidal thoughts and ideas, although this notion remains controversial.

In 2004, the U.S. Food and Drug Administration (FDA) recommended that the class of drugs known as selective serotonin reuptake inhibitors (SSRIs) carry a strong "black box" warning on the label outlining the possibility of an increase in suicidal ideation. SSRIs include widely used drugs such as Celexa, Paxil, Prozac and Zoloft.

The black box warning was based on studies that found that 4 percent of the group taking SSRIs had suicidal ideation, compared with 2 percent of the group taking a placebo.