Bipolar disorder has a genetic link that may explain why many sufferers attempt suicide, researchers at Johns Hopkins say.
An estimated 1.4 percent of Americans die from suicide and about 4.6 percent of people have tried to kill themselves at least once, the researchers said.
For those with bipolar disorder, the percentage who think about suicide is 47 percent, with a quarter actually trying, HealthJockey.com reports.
The link was found in a small region on chromosome 2 that contains four genes, including the ACP1 gene.
Those people with more than normal levels of ACP1 protein in the brain were more likely to attempt suicide, the researchers said.
Virginia L. Willour, study leaders and an assistant professor of psychiatry and behavioral sciences at the Johns Hopkins University School of Medicine, said in a statement, "We have long believed that genes play a role in what makes the difference between thinking about suicide and actually doing it."
HealthJockey.com reports that she and other researchers studied the DNA of thousands of people with bipolar disorder.
More extra protein meant that the patients were more likely to attempt suicide.
The protein is thought to influence the same biological pathway as lithium, which is used to reduce suicidal behavior but has serious side effects that prevent many depression sufferers from taking it.
The findings, reported in the journal Molecular Psychiatry, may lead to a new kind of treatment, reports HealthJockey.com.
