Genetic Link to Suicidal Tendencies Nailed Down

FRIDAY, Feb. 23, 2007 (HealthDay News) -- For the third time, geneticists have linked a particular area of chromosome 2 to attempted suicide, a finding which may help identify people at risk and even lead to new drug therapies.

"My goal would be to allow us to identify who is at high risk and to give pharmaceutical companies a target pathway that they can then design drugs for," said study author Virginia Willour, an assistant professor of psychiatry and behavioral sciences at Johns Hopkins School of Medicine in Baltimore.

The previous two studies, both of which came out recently, looked at attempted suicide in families with alcoholism and with early-onset major depression. The current study, published in the March issue of Biological Psychiatry, looked at people with bipolar disorder.

"We're all in the same place. This is fantastic for geneticists interested in finding genetic risk factors," Willour said. "We all found the same region. That's pretty unusual, because you may be in sort of the same ballpark, but these were right on top of each other."

"Attempted suicide and suicide are very dramatic and worrisome outcomes in psychiatric patients," added Dr. Ma-Li Wong, a professor of psychiatry and vice chair for translational research at the University of Miami Miller School of Medicine. "This study and two other studies have pointed to this chromosome region as linked to suicide attempts, so people who commit suicide are likely to have some variation on this region."

"This is the third replication of this finding, so it's enough for us to say that it is likely these genes may be related to suicide," Wong continued.

Suicide remains a leading cause of death in the United States with, according to Willour, about 4.6 percent of Americans aged 15 to 54 having tried to end their lives.

Previous studies have provided strong evidence for a genetic component to this type of behavior, often in conjunction with psychiatric disorders, especially mood disorders and alcoholism.

But the propensity to attempt suicide may have its own genetic roots.

"In the research, the thought is that part of the risk for suicidal behavior comes from inheritance of a psychiatric disorder such as bipolar disorder or depression, but there may be another risk factor above and beyond that," Willour explained. "This study would be getting at that, the risk factor that goes across diagnoses. What makes you go from thinking to acting, because thinking is pretty common, but acting is less so."

For this study, Willour's team tested the entire genome of 417 members of 162 families with bipolar disorder and a history of attempted suicide. There are 20,000 to 25,000 genes in the genome.

Participants with a history of both attempted suicide and bipolar disorder showed similarities in a certain area of the genome: DNA marker D2S1777, on a section of chromosome 2 referred to as 2p12.

According to Willour, there are about 170 genes in the candidate region, and researchers now need to sift through them to find a culprit gene or genes.

"What we'd really like to do is know who's at high risk and have drug companies come in and address drugs," Willour said. "It'd be nice to be able to tell ahead of time if you are at high risk and which would be the best medications for you to take."

More information

Learn more about suicide from the U.S. Centers for Disease Control and Prevention.