In a study published in the journal Molecular Psychiatry entitled “A genome-wide association study of attempted suicide,” a group of Johns Hopkins researchers (Willour, et al.) report the discovery of a “a small region on chromosome 2 that is associated with increased risk for attempted suicide.”

Willour and her colleagues studied DNA samples from nearly 2,700 adults with bipolar disorder, 1,201 of them with a history of suicide attempts and 1,497 without. They found that those with one copy of a genetic variant in the region of chromosome 2 where ACP1 is located were 1.4 times more likely to have attempted suicide, and those with two copies were almost three times as likely.

Willour and her colleagues were able to replicate their findings in another group of samples: This one comprised DNA from more than 3,000 people with bipolar disorder. By using only DNA from people with bipolar disorder, the researchers say they were able to control for mental illness and narrow in on what may cause one group to attempt suicide and another to control those urges.

Suicide is estimated to kill 1.4 percent of the U.S. population, and roughly 4.6 percent of the population has attempted suicide at least once, Willour says. Among people with bipolar disorder, 47 percent think about killing themselves while 25 percent actually try to do it, she says.

From Johns Hopkins Press Release “Johns Hopkins Team Identifies Genetic Link to Attempted Suicide”

Perhaps most interesting is that researchers found, in the brains of those who had the gene variant, higher levels of the ACP1 protein, which is thought to influence the same biological pathway as lithium, a medication known to reduce the rate of suicidal behavior.

We have known for some time that lithium may reduce the risk of suicide ideation and attempt and that a certain subgroup of individuals seems to have both a higher risk of suicide and a higher response rate to lithium. Researchers have been exploring genetic contributions to these patterns, and this study identifies a particular gene that may be involved and may be useful as a marker.

It would be enormously valuable to be able to identify people at higher risk of suicide and those who would benefit from lithium as a first choice medicine. The researchers hope that their findings might lead to improvements in suicide prevention by opening new avenues to research and development – alternatives to lithium for people who can’t tolerate it, or perhaps even more effective medications for preventing suicide thinking and behaviors.

Photo by Jason Kuffer, available under a Creative Commons attribution license.

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    Last reviewed: 30 Mar 2011